{
  "title": "Collection and Organisation of Data - Grade 7 CBSE",
  "total_questions": 150,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "What is data?", "options": {"A": "Numbers only", "B": "Facts and figures", "C": "Graphs and charts", "D": "Calculations"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "Which is an example of primary data?", "options": {"A": "Data from internet", "B": "Data from books", "C": "Data collected by yourself", "D": "Data from government reports"}, "correct_answer": "C"},
    {"id": 3, "difficulty": "easy", "question": "What is secondary data?", "options": {"A": "Data collected firsthand", "B": "Data collected by someone else", "C": "Numerical data only", "D": "Categorical data only"}, "correct_answer": "B"},
    {"id": 4, "difficulty": "easy", "question": "Which is a method of data collection?", "options": {"A": "Survey", "B": "Observation", "C": "Experiment", "D": "All of these"}, "correct_answer": "D"},
    {"id": 5, "difficulty": "easy", "question": "What is a survey?", "options": {"A": "Asking questions to collect data", "B": "Observing without interference", "C": "Conducting experiments", "D": "Analyzing existing data"}, "correct_answer": "A"},
    {"id": 6, "difficulty": "easy", "question": "Which is qualitative data?", "options": {"A": "Height of students", "B": "Weight of objects", "C": "Favorite colors", "D": "Test scores"}, "correct_answer": "C"},
    {"id": 7, "difficulty": "easy", "question": "Which is quantitative data?", "options": {"A": "Types of cars", "B": "Brands of phones", "C": "Number of books", "D": "Names of students"}, "correct_answer": "C"},
    {"id": 8, "difficulty": "easy", "question": "What is raw data?", "options": {"A": "Organized data", "B": "Unorganized collected data", "C": "Analyzed data", "D": "Graphical data"}, "correct_answer": "B"},
    {"id": 9, "difficulty": "easy", "question": "Why do we organize data?", "options": {"A": "To make it look neat", "B": "To make it easier to understand", "C": "To waste time", "D": "To make it longer"}, "correct_answer": "B"},
    {"id": 10, "difficulty": "easy", "question": "What is frequency in data?", "options": {"A": "Height of bar", "B": "Number of times data occurs", "C": "Average of data", "D": "Range of data"}, "correct_answer": "B"},
    {"id": 11, "difficulty": "easy", "question": "Which is a data collection tool?", "options": {"A": "Questionnaire", "B": "Bar graph", "C": "Pie chart", "D": "Frequency table"}, "correct_answer": "A"},
    {"id": 12, "difficulty": "easy", "question": "What is observation method?", "options": {"A": "Asking questions", "B": "Watching and recording", "C": "Conducting tests", "D": "Reading books"}, "correct_answer": "B"},
    {"id": 13, "difficulty": "easy", "question": "What is discrete data?", "options": {"A": "Data that can take any value", "B": "Data with clear separations", "C": "Continuous measurements", "D": "Decimal numbers"}, "correct_answer": "B"},
    {"id": 14, "difficulty": "easy", "question": "What is continuous data?", "options": {"A": "Whole numbers only", "B": "Can take any value in range", "C": "Categories only", "D": "Yes/No answers"}, "correct_answer": "B"},
    {"id": 15, "difficulty": "easy", "question": "Which is an example of discrete data?", "options": {"A": "Temperature", "B": "Height", "C": "Number of students", "D": "Weight"}, "correct_answer": "C"},
    {"id": 16, "difficulty": "easy", "question": "What is a tally mark?", "options": {"A": "A check mark", "B": "A vertical line for counting", "C": "A cross mark", "D": "A circle"}, "correct_answer": "B"},
    {"id": 17, "difficulty": "easy", "question": "How many tally marks in a group?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "C"},
    {"id": 18, "difficulty": "easy", "question": "What is range of data?", "options": {"A": "Difference between max and min", "B": "Average of data", "C": "Middle value", "D": "Most frequent value"}, "correct_answer": "A"},
    {"id": 19, "difficulty": "easy", "question": "What is first step in data handling?", "options": {"A": "Make graphs", "B": "Collect data", "C": "Analyze data", "D": "Draw conclusions"}, "correct_answer": "B"},
    {"id": 20, "difficulty": "easy", "question": "Why is data organization important?", "options": {"A": "Reveals patterns", "B": "Makes analysis easier", "C": "Helps in decision making", "D": "All of these"}, "correct_answer": "D"},
    
    {"id": 21, "difficulty": "medium", "question": "Data collected on favorite fruits: Apple=15, Banana=12, Orange=18, Mango=20. What is total number of responses?", "options": {"A": "60", "B": "65", "C": "70", "D": "75"}, "correct_answer": "B"},
    {"id": 22, "difficulty": "medium", "question": "In a survey of 50 students about mode of transport: Walk=15, Cycle=10, Bus=20, Car=5. What percentage use Bus?", "options": {"A": "30%", "B": "35%", "C": "40%", "D": "45%"}, "correct_answer": "C"},
    {"id": 23, "difficulty": "medium", "question": "Raw data: 5, 8, 6, 5, 7, 8, 9, 5, 6, 7, 8, 5, 6, 7, 8, 9, 5, 6. What is frequency of 5?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "C"},
    {"id": 24, "difficulty": "medium", "question": "Data on test scores: 45, 50, 55, 60, 65, 70, 75, 80, 85, 90. If grouped as 40-49, 50-59, etc., how many in 60-69?", "options": {"A": "2", "B": "3", "C": "4", "D": "5"}, "correct_answer": "B"},
    {"id": 25, "difficulty": "medium", "question": "Temperature recorded every hour: 25°, 26°, 27°, 28°, 29°, 30°. What is the range?", "options": {"A": "4°", "B": "5°", "C": "6°", "D": "7°"}, "correct_answer": "B"},
    {"id": 26, "difficulty": "medium", "question": "In data: 12, 15, 18, 21, 24, 27, 30. If grouped with class width 5 starting from 10, how many classes?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "C"},
    {"id": 27, "difficulty": "medium", "question": "Data on family size: 3, 4, 5, 3, 4, 6, 4, 5, 3, 4, 5, 6, 4, 3. What is modal family size?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "B"},
     {
    "id": 28,
    "difficulty": "medium",
    "question": "Survey on pet ownership: Dog=25, Cat=20, Bird=15, Fish=10, None=30. What fraction have pets?",
    "options": {
      "A": "7/10",
      "B": "3/5",
      "C": "2/3",
      "D": "5/9"
    },
    "correct_answer": "A"
  }, {"id": 29, "difficulty": "medium", "question": "Data: 10, 15, 20, 25, 30, 35, 40, 45, 50. If class intervals are 10-19, 20-29, etc., what is frequency of 30-39?", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "B"},
    {"id": 30, "difficulty": "medium", "question": "Heights in cm: 150, 152, 155, 158, 160, 162, 165, 168, 170. What is range?", "options": {"A": "18", "B": "19", "C": "20", "D": "21"}, "correct_answer": "C"},
    {"id": 31, "difficulty": "medium", "question": "In a class of 40, data on siblings: 0=8, 1=15, 2=12, 3=5. What percentage have 2 or more siblings?", "options": {"A": "35%", "B": "40%", "C": "42.5%", "D": "45%"}, "correct_answer": "C"},
    {"id": 32, "difficulty": "medium", "question": "Test scores: 35, 40, 45, 50, 55, 60, 65, 70, 75, 80. If grouped as 35-44, 45-54, etc., what is class mark of 55-64?", "options": {"A": "58.5", "B": "59", "C": "59.5", "D": "60"}, "correct_answer": "C"},
    {"id": 33, "difficulty": "medium", "question": "Data on travel time: 15, 20, 25, 30, 35, 40, 45, 50 minutes. What is median?", "options": {"A": "30", "B": "32.5", "C": "35", "D": "37.5"}, "correct_answer": "B"},
    {"id": 34, "difficulty": "medium", "question": "Survey on favorite subject: Math=30, Science=25, English=20, History=15, Geography=10. What is ratio of Math to Geography?", "options": {"A": "2:1", "B": "3:1", "C": "4:1", "D": "5:1"}, "correct_answer": "B"},
    {"id": 35, "difficulty": "medium", "question": "Data: 5, 7, 9, 11, 13, 15, 17, 19, 21. What is mean?", "options": {"A": "11", "B": "12", "C": "13", "D": "14"}, "correct_answer": "C"},
    {"id": 36, "difficulty": "medium", "question": "Ages: 10, 11, 12, 13, 14, 15. If grouped as 10-12 and 13-15, what is frequency of first group?", "options": {"A": "2", "B": "3", "C": "4", "D": "5"}, "correct_answer": "B"},
    {"id": 37, "difficulty": "medium", "question": "Data on books read: 0-2=10, 3-5=15, 6-8=20, 9-11=5. How many read more than 5 books?", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 38, "difficulty": "medium", "question": "Weights in kg: 40, 42, 45, 48, 50, 52, 55, 58, 60. What is range?", "options": {"A": "18", "B": "19", "C": "20", "D": "21"}, "correct_answer": "C"},
    {"id": 39, "difficulty": "medium", "question": "Data: 12, 15, 18, 21, 24, 27, 30, 33, 36. What is frequency of numbers divisible by 6?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "C"},
    {"id": 40, "difficulty": "medium", "question": "Survey on ice cream flavors: Chocolate=40, Vanilla=30, Strawberry=20, Butterscotch=10. What angle represents Vanilla in pie chart?", "options": {"A": "90°", "B": "108°", "C": "120°", "D": "135°"}, "correct_answer": "B"},
    {"id": 41, "difficulty": "medium", "question": "Test marks: 55, 60, 65, 70, 75, 80, 85, 90, 95. What percentage scored above 75?", "options": {"A": "44.4%", "B": "50%", "C": "55.6%", "D": "60%"}, "correct_answer": "C"},
     {
    "id": 42,
    "difficulty": "medium",
    "question": "Data: 8, 12, 16, 20, 24, 28, 32, 36, 40. What is mean deviation from mean?",
    "options": {
      "A": "8.0",
      "B": "8.5",
      "C": "8.9",
      "D": "9.5"
    },
    "correct_answer": "C"
  }, {"id": 43, "difficulty": "medium", "question": "Ages in years: 11, 12, 13, 14, 15, 16. If grouped as 11-13 and 14-16, what is ratio of frequencies?", "options": {"A": "1:1", "B": "2:1", "C": "1:2", "D": "3:2"}, "correct_answer": "A"},
    {"id": 44, "difficulty": "medium", "question": "Data on distance traveled: 5, 10, 15, 20, 25, 30 km. What is average?", "options": {"A": "15.5", "B": "16.5", "C": "17.5", "D": "18.5"}, "correct_answer": "C"},
    {"id": 45, "difficulty": "medium", "question": "Survey results: Yes=60, No=40. What percentage said No?", "options": {"A": "30%", "B": "35%", "C": "40%", "D": "45%"}, "correct_answer": "C"},
    {"id": 46, "difficulty": "medium", "question": "Data: 7, 14, 21, 28, 35, 42, 49, 56, 63. How many are multiples of 14?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "B"},
    {"id": 47, "difficulty": "medium", "question": "Heights: 140, 145, 150, 155, 160, 165, 170 cm. What is median?", "options": {"A": "150", "B": "155", "C": "160", "D": "165"}, "correct_answer": "B"},
    {"id": 48, "difficulty": "medium", "question": "Data on daily steps: 5000, 6000, 7000, 8000, 9000, 10000. What is range?", "options": {"A": "4000", "B": "4500", "C": "5000", "D": "5500"}, "correct_answer": "C"},
    {"id": 49, "difficulty": "medium", "question": "Survey on breakfast: Cereal=25, Toast=20, Fruits=15, Eggs=30, None=10. What fraction eat cereal or toast?", "options": {"A": "9/20", "B": "1/2", "C": "11/20", "D": "3/5"}, "correct_answer": "A"},
    {"id": 50, "difficulty": "medium", "question": "Data: 3, 6, 9, 12, 15, 18, 21, 24, 27. What is sum of data?", "options": {"A": "120", "B": "135", "C": "150", "D": "165"}, "correct_answer": "B"},
    {"id": 51, "difficulty": "medium", "question": "Ages: 13, 14, 15, 16, 17, 18. What is mean age?", "options": {"A": "15", "B": "15.5", "C": "16", "D": "16.5"}, "correct_answer": "B"},
    {"id": 52, "difficulty": "medium", "question": "Data on siblings: 0, 1, 2, 3, 4. Frequencies: 10, 15, 20, 10, 5. What is mode?", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "B"},
    {"id": 53, "difficulty": "medium", "question": "Test scores: 40, 45, 50, 55, 60, 65, 70, 75, 80. How many scored at least 60?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "C"},
    {"id": 54, "difficulty": "medium", "question": "Data: 11, 22, 33, 44, 55, 66, 77, 88, 99. What is average of first and last?", "options": {"A": "50", "B": "55", "C": "60", "D": "65"}, "correct_answer": "B"},
    {"id": 55, "difficulty": "medium", "question": "Survey on hobbies: Reading=35, Sports=25, Music=20, Art=15, Dance=5. What percentage prefer Sports or Music?", "options": {"A": "40%", "B": "45%", "C": "50%", "D": "55%"}, "correct_answer": "B"},
    {"id": 56, "difficulty": "medium", "question": "Data: 5, 10, 15, 20, 25, 30, 35, 40, 45. What is frequency of multiples of 10?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "B"},
    {"id": 57, "difficulty": "medium", "question": "Weights: 30, 35, 40, 45, 50, 55, 60 kg. What is range?", "options": {"A": "25", "B": "27", "C": "29", "D": "30"}, "correct_answer": "D"},
    {"id": 58, "difficulty": "medium", "question": "Data on pets: Dog=40, Cat=30, Bird=20, Fish=10. What is ratio of Cat to Fish?", "options": {"A": "2:1", "B": "3:1", "C": "4:1", "D": "5:1"}, "correct_answer": "B"},
    {"id": 59, "difficulty": "medium", "question": "Ages: 10, 11, 12, 13, 14, 15, 16. What is median?", "options": {"A": "12", "B": "12.5", "C": "13", "D": "13.5"}, "correct_answer": "C"},
    {"id": 60, "difficulty": "medium", "question": "Data: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. What percentage are perfect squares?", "options": {"A": "10%", "B": "15%", "C": "20%", "D": "25%"}, "correct_answer": "C"},
    {"id": 61, "difficulty": "medium", "question": "Survey on transport: Walk=20, Cycle=15, Bus=30, Car=25, Metro=10. What fraction use public transport (Bus+Metro)?", "options": {"A": "2/5", "B": "3/8", "C": "5/12", "D": "7/15"}, "correct_answer": "A"},
    {"id": 62, "difficulty": "medium", "question": "Data: 9, 18, 27, 36, 45, 54, 63, 72, 81. What is sum?", "options": {"A": "405", "B": "415", "C": "425", "D": "435"}, "correct_answer": "A"},
    {"id": 63, "difficulty": "medium", "question": "Test scores: 35, 40, 45, 50, 55, 60, 65, 70. What is average?", "options": {"A": "50", "B": "52.5", "C": "55", "D": "57.5"}, "correct_answer": "B"},
    {"id": 64, "difficulty": "medium", "question": "Data on siblings: 0=8, 1=12, 2=15, 3=10, 4=5. What percentage have 1 or 2 siblings?", "options": {"A": "48%", "B": "52%", "C": "54%", "D": "56%"}, "correct_answer": "C"},
    {"id": 65, "difficulty": "medium", "question": "Data: 7, 14, 21, 28, 35, 42, 49, 56. What is mean?", "options": {"A": "28", "B": "30", "C": "31.5", "D": "33"}, "correct_answer": "C"},
    {"id": 66, "difficulty": "medium", "question": "Heights: 130, 135, 140, 145, 150, 155, 160 cm. What is range?", "options": {"A": "25", "B": "28", "C": "30", "D": "32"}, "correct_answer": "C"},
    {"id": 67, "difficulty": "medium", "question": "Survey on movies: Action=30, Comedy=25, Drama=20, Horror=15, Sci-fi=10. What angle for Drama in pie chart?", "options": {"A": "60°", "B": "72°", "C": "84°", "D": "96°"}, "correct_answer": "B"},
    {"id": 68, "difficulty": "medium", "question": "Data: 4, 8, 12, 16, 20, 24, 28, 32, 36. How many are divisible by 8?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "B"},
    {"id": 69, "difficulty": "medium", "question": "Ages: 12, 13, 14, 15, 16, 17, 18. What is mode?", "options": {"A": "No mode", "B": "14", "C": "15", "D": "16"}, "correct_answer": "A"},
    {"id": 70, "difficulty": "medium", "question": "Data on books: 1-3=15, 4-6=20, 7-9=25, 10-12=10. How many read 4 or more books?", "options": {"A": "45", "B": "50", "C": "55", "D": "60"}, "correct_answer": "C"},
    {"id": 71, "difficulty": "medium", "question": "Weights: 25, 30, 35, 40, 45, 50, 55 kg. What is median?", "options": {"A": "35", "B": "37.5", "C": "40", "D": "42.5"}, "correct_answer": "C"},
    {"id": 72, "difficulty": "medium", "question": "Data: 6, 12, 18, 24, 30, 36, 42, 48, 54. What is average?", "options": {"A": "27", "B": "29", "C": "30", "D": "32"}, "correct_answer": "C"},
    {"id": 73, "difficulty": "medium", "question": "Survey on sports: Cricket=40, Football=30, Basketball=20, Tennis=10. What percentage play Cricket or Football?", "options": {"A": "60%", "B": "65%", "C": "70%", "D": "75%"}, "correct_answer": "C"},
    {"id": 74, "difficulty": "medium", "question": "Data: 5, 10, 15, 20, 25, 30, 35, 40. What is range?", "options": {"A": "30", "B": "32", "C": "34", "D": "35"}, "correct_answer": "D"},
    {"id": 75, "difficulty": "medium", "question": "Test scores: 50, 55, 60, 65, 70, 75, 80, 85, 90. What percentage scored above 70?", "options": {"A": "44.4%", "B": "50%", "C": "55.6%", "D": "60%"}, "correct_answer": "C"},
    {"id": 76, "difficulty": "medium", "question": "Data: 8, 16, 24, 32, 40, 48, 56, 64, 72. What is sum of first and last?", "options": {"A": "78", "B": "80", "C": "82", "D": "84"}, "correct_answer": "B"},
    {"id": 77, "difficulty": "medium", "question": "Ages: 11, 12, 13, 14, 15. What is mean?", "options": {"A": "12", "B": "12.5", "C": "13", "D": "13.5"}, "correct_answer": "C"},
     {
    "id": 78,
    "difficulty": "medium",
    "question": "Data on pets: 0=20, 1=25, 2=30, 3=15, 4=10. What is average pets per person?",
    "options": {
      "A": "1.5",
      "B": "1.6",
      "C": "1.7",
      "D": "1.8"
    },
    "correct_answer": "C"
  }, {"id": 79, "difficulty": "medium", "question": "Data: 3, 6, 9, 12, 15, 18, 21, 24. What is frequency of multiples of 6?", "options": {"A": "3", "B": "4", "C": "5", "D": "6"}, "correct_answer": "B"},
    {"id": 80, "difficulty": "medium", "question": "Survey on fruits: Apple=35, Banana=25, Orange=20, Mango=15, Grapes=5. What fraction prefer Apple or Banana?", "options": {"A": "3/5", "B": "13/20", "C": "7/10", "D": "4/5"}, "correct_answer": "A"},
    
    {"id": 81, "difficulty": "hard", "question": "Data collected on daily screen time (hours): 2, 3, 4, 5, 6, 7, 8 with frequencies: 5, 10, 15, 20, 25, 15, 10. Find mean screen time.", "options": {"A": "4.8", "B": "5.2", "C": "5.5", "D": "5.8"}, "correct_answer": "C"},
    {"id": 82, "difficulty": "hard", "question": "In a survey of 200 students, data on favorite subjects: Math=30%, Science=25%, English=20%, History=15%, Geography=10%. If each subject has boys and girls in ratio 3:2, find number of girls who prefer Math.", "options": {"A": "18", "B": "24", "C": "30", "D": "36"}, "correct_answer": "B"},
    {"id": 83, "difficulty": "hard", "question": "Data grouped in classes: 0-10=5, 10-20=12, 20-30=18, 30-40=15, 40-50=10. Find the mean using assumed mean method with A=25.", "options": {"A": "24.5", "B": "25.5", "C": "26.5", "D": "27.5"}, "correct_answer": "C"},
    {"id": 84, "difficulty": "hard", "question": "In a frequency distribution, mean=45, median=43, mode=40. If total frequency=100, and data is moderately skewed, estimate sum of frequencies of classes below median.", "options": {"A": "40-45", "B": "45-50", "C": "50-55", "D": "55-60"}, "correct_answer": "B"},
    {"id": 85, "difficulty": "hard", "question": "Data on monthly savings (₹): 1000, 1500, 2000, 2500, 3000 with frequencies: 10, 15, 20, 25, 30. Find the amount that represents 75th percentile.", "options": {"A": "₹2500", "B": "₹2750", "C": "₹3000", "D": "₹3250"}, "correct_answer": "A"},
    {"id": 86, "difficulty": "hard", "question": "In a cumulative frequency distribution: Less than 10=5, less than 20=15, less than 30=30, less than 40=45, less than 50=55. Find the interquartile range.", "options": {"A": "15", "B": "18", "C": "20", "D": "22"}, "correct_answer": "C"},
    {"id": 87, "difficulty": "hard", "question": "Data on test scores out of 100 for 80 students has mean=65, median=67, mode=70. If highest score is 95 and lowest is 35, estimate standard deviation using range rule of thumb.", "options": {"A": "10", "B": "12", "C": "14", "D": "15"}, "correct_answer": "D"},
    {"id": 88, "difficulty": "hard", "question": "In a pie chart representing 360 students' preferences, Math section has angle 90°. If this section is divided into Boys and Girls in ratio 4:5, find number of Girls preferring Math.", "options": {"A": "100", "B": "112.5", "C": "125", "D": "137.5"}, "correct_answer": "C"},
    {"id": 89, "difficulty": "hard", "question": "Data collected over 5 years: Year1=100, Year2=120, Year3=144, Year4=172.8, Year5=207.36. Identify the growth pattern and predict Year6.", "options": {"A": "228.096", "B": "238.878", "C": "248.832", "D": "259.2"}, "correct_answer": "C"},
    {"id": 90, "difficulty": "hard", "question": "In a frequency distribution with classes 0-10, 10-20, etc., if mean=32.5 and assumed mean=35 with Σfd=-50 and total frequency=100, find correct mean.", "options": {"A": "32", "B": "32.5", "C": "33", "D": "33.5"}, "correct_answer": "B"},
    {"id": 91, "difficulty": "hard", "question": "Data on family income (₹'000): 20-30=10, 30-40=15, 40-50=25, 50-60=30, 60-70=20. Find modal class and approximate mode using formula.", "options": {"A": "50-60, ₹54,000", "B": "50-60, ₹56,000", "C": "40-50, ₹46,000", "D": "40-50, ₹48,000"}, "correct_answer": "A"},
    {"id": 92, "difficulty": "hard", "question": "In a survey of 500 people, 60% prefer Tea, 40% prefer Coffee. Among Tea drinkers, 70% add Sugar. Among Coffee drinkers, 80% add Sugar. Find percentage of all people who add Sugar.", "options": {"A": "68%", "B": "70%", "C": "72%", "D": "74%"}, "correct_answer": "D"},
    {"id": 93, "difficulty": "hard", "question": "Data on marks: 0-20=5%, 20-40=15%, 40-60=25%, 60-80=35%, 80-100=20%. If 200 students scored above 60, find total students and number in 40-60 range.", "options": {"A": "400, 100", "B": "400, 120", "C": "500, 125", "D": "500, 150"}, "correct_answer": "C"},
    {"id": 94, "difficulty": "hard", "question": "In a time series data: Jan=100, Feb=110, Mar=121, Apr=133.1, May=146.41. Find the average monthly growth rate.", "options": {"A": "8%", "B": "9%", "C": "10%", "D": "11%"}, "correct_answer": "C"},
    {"id": 95, "difficulty": "hard", "question": "Data on ages has mean=25, median=23, mode=21. If distribution is moderately skewed right, estimate relationship between mean, median, mode.", "options": {"A": "Mean > Median > Mode", "B": "Mode > Median > Mean", "C": "Median > Mean > Mode", "D": "Mean = Median = Mode"}, "correct_answer": "A"},
    {"id": 96, "difficulty": "hard", "question": "In a grouped data with classes 0-10, 10-20,..., 90-100, if mean=52.5 and assumed mean=55 with Σfd=-125 and N=250, find class width and correct mean.", "options": {"A": "10, 52.5", "B": "10, 52", "C": "10, 53", "D": "5, 52.5"}, "correct_answer": "A"},
    {"id": 97, "difficulty": "hard", "question": "Data on daily steps: 4000-5000=10, 5000-6000=15, 6000-7000=25, 7000-8000=30, 8000-9000=20. Find median steps using interpolation.", "options": {"A": "6666.67", "B": "6833.33", "C": "7000", "D": "7166.67"}, "correct_answer": "B"},
    {"id": 98, "difficulty": "hard", "question": "In a normal distribution of 1000 items with mean=500 and SD=50, estimate number of items between 450 and 550 using empirical rule.", "options": {"A": "500", "B": "600", "C": "680", "D": "750"}, "correct_answer": "C"},
    {"id": 99, "difficulty": "hard", "question": "Data on income has Q1=₹20,000, Q3=₹40,000, median=₹30,000. Find coefficient of quartile deviation and interquartile range.", "options": {"A": "0.333, ₹20,000", "B": "0.333, ₹25,000", "C": "0.4, ₹20,000", "D": "0.4, ₹25,000"}, "correct_answer": "A"},
    {"id": 100, "difficulty": "hard", "question": "In a bimodal distribution with modes at 25 and 35, mean=30, median=32. If total frequency=200, estimate approximate frequencies around modes assuming symmetric distribution.", "options": {"A": "Mode1=40, Mode2=40", "B": "Mode1=35, Mode2=35", "C": "Mode1=30, Mode2=30", "D": "Mode1=25, Mode2=25"}, "correct_answer": "C"}
  ,
 {"id":101,"difficulty":"easy","question":"Which of the following best describes statistical data?","options":{"A":"Random guesses","B":"Collected information","C":"Only numbers","D":"Only graphs"},"correct_answer":"B"},
    {"id":102,"difficulty":"easy","question":"Data collected directly from students in a class is called:","options":{"A":"Secondary data","B":"Published data","C":"Primary data","D":"Tabulated data"},"correct_answer":"C"},
    {"id":103,"difficulty":"easy","question":"Which source provides secondary data?","options":{"A":"Questionnaire","B":"Interview","C":"Census report","D":"Observation"},"correct_answer":"C"},
    {"id":104,"difficulty":"easy","question":"Which type of data represents categories such as colour or type?","options":{"A":"Discrete","B":"Continuous","C":"Qualitative","D":"Quantitative"},"correct_answer":"C"},
    {"id":105,"difficulty":"easy","question":"Which of the following represents quantitative data?","options":{"A":"Favourite sport","B":"Number of siblings","C":"Type of vehicle","D":"Eye colour"},"correct_answer":"B"},
    {"id":106,"difficulty":"easy","question":"Unarranged data collected initially is called:","options":{"A":"Grouped data","B":"Raw data","C":"Primary table","D":"Frequency data"},"correct_answer":"B"},
    {"id":107,"difficulty":"easy","question":"What is the purpose of organizing data?","options":{"A":"Decoration","B":"Easy interpretation","C":"Increasing values","D":"Removing errors"},"correct_answer":"B"},
    {"id":108,"difficulty":"easy","question":"Which term means the number of times an observation occurs?","options":{"A":"Range","B":"Frequency","C":"Mean","D":"Class"},"correct_answer":"B"},
    {"id":109,"difficulty":"easy","question":"Which tool is used to record data quickly during collection?","options":{"A":"Bar graph","B":"Pie chart","C":"Tally marks","D":"Histogram"},"correct_answer":"C"},
    {"id":110,"difficulty":"easy","question":"A group of five tally marks represents:","options":{"A":"3","B":"4","C":"5","D":"6"},"correct_answer":"C"},
    {"id":111,"difficulty":"easy","question":"Which data can take fractional values?","options":{"A":"Discrete","B":"Qualitative","C":"Continuous","D":"Categorical"},"correct_answer":"C"},
    {"id":112,"difficulty":"easy","question":"Which data shows number of students in a class?","options":{"A":"Continuous","B":"Discrete","C":"Qualitative","D":"Nominal"},"correct_answer":"B"},
    {"id":113,"difficulty":"easy","question":"The difference between highest and lowest observation is called:","options":{"A":"Mean","B":"Median","C":"Range","D":"Mode"},"correct_answer":"C"},
    {"id":114,"difficulty":"easy","question":"Which is the first step in data handling?","options":{"A":"Analysis","B":"Tabulation","C":"Collection","D":"Representation"},"correct_answer":"C"},
    {"id":115,"difficulty":"easy","question":"Which chart is best for showing parts of a whole?","options":{"A":"Bar graph","B":"Line graph","C":"Pie chart","D":"Histogram"},"correct_answer":"C"},
    {"id":116,"difficulty":"easy","question":"Which data collection method involves watching events?","options":{"A":"Survey","B":"Observation","C":"Questionnaire","D":"Interview"},"correct_answer":"B"},
    {"id":117,"difficulty":"easy","question":"Which of the following is NOT data?","options":{"A":"Marks obtained","B":"Student names","C":"Teacher opinion","D":"Roll numbers"},"correct_answer":"C"},
    {"id":118,"difficulty":"easy","question":"Which data type uses whole numbers only?","options":{"A":"Continuous","B":"Discrete","C":"Qualitative","D":"Grouped"},"correct_answer":"B"},
    {"id":119,"difficulty":"easy","question":"Why are tally marks grouped in fives?","options":{"A":"Decoration","B":"Easy counting","C":"Save space","D":"Looks neat"},"correct_answer":"B"},
    {"id":120,"difficulty":"easy","question":"Which representation uses rectangular bars?","options":{"A":"Pie chart","B":"Histogram","C":"Bar graph","D":"Line graph"},"correct_answer":"C"},

    {"id":121,"difficulty":"medium","question":"Marks obtained by 5 students are 12, 15, 18, 20, 25. What is the mean?","options":{"A":"17","B":"18","C":"19","D":"20"},"correct_answer":"C"},
    {"id":122,"difficulty":"medium","question":"Find the range of data: 42, 35, 50, 47, 38.","options":{"A":"12","B":"13","C":"15","D":"18"},"correct_answer":"B"},
    {"id":123,"difficulty":"medium","question":"Data: 4, 6, 8, 6, 9, 6, 7. What is the mode?","options":{"A":"6","B":"7","C":"8","D":"9"},"correct_answer":"A"},
    {"id":124,"difficulty":"medium","question":"Number of absentees in 7 days: 2, 3, 4, 3, 5, 3, 2. What is the median?","options":{"A":"2","B":"3","C":"4","D":"5"},"correct_answer":"B"},
    {"id":125,"difficulty":"medium","question":"If the maximum value is 80 and minimum is 25, what is the range?","options":{"A":"45","B":"50","C":"55","D":"60"},"correct_answer":"C"},
    {"id":126,"difficulty":"medium","question":"Which measure tells the most frequent observation?","options":{"A":"Mean","B":"Median","C":"Mode","D":"Range"},"correct_answer":"C"},
    {"id":127,"difficulty":"medium","question":"Data: 10, 20, 30, 40, 50. What is the median?","options":{"A":"20","B":"25","C":"30","D":"35"},"correct_answer":"C"},
    {"id":128,"difficulty":"medium","question":"In a pie chart, a category represents 90°. What fraction of data is this?","options":{"A":"1/2","B":"1/3","C":"1/4","D":"1/5"},"correct_answer":"C"},
    {"id":129,"difficulty":"medium","question":"Which graph is suitable to compare quantities?","options":{"A":"Pie chart","B":"Bar graph","C":"Histogram","D":"Line graph"},"correct_answer":"B"},
    {"id":130,"difficulty":"medium","question":"Find the mean of first five even numbers.","options":{"A":"4","B":"5","C":"6","D":"8"},"correct_answer":"B"},
    {"id":131,"difficulty":"medium","question":"If frequencies are added, the total obtained is called:","options":{"A":"Range","B":"Class width","C":"Total frequency","D":"Mode"},"correct_answer":"C"},
    {"id":132,"difficulty":"medium","question":"Which measure of central tendency uses positional value?","options":{"A":"Mean","B":"Mode","C":"Median","D":"Range"},"correct_answer":"C"},
    {"id":133,"difficulty":"medium","question":"Data: 2, 4, 6, 8, 10, 12. What is the mean?","options":{"A":"6","B":"7","C":"8","D":"9"},"correct_answer":"B"},
    {"id":134,"difficulty":"medium","question":"In grouped data, class mark is calculated as:","options":{"A":"Upper limit","B":"Lower limit","C":"Average of limits","D":"Difference of limits"},"correct_answer":"C"},
    {"id":135,"difficulty":"medium","question":"Which representation is circular in shape?","options":{"A":"Bar graph","B":"Line graph","C":"Histogram","D":"Pie chart"},"correct_answer":"D"},

    {"id":136,"difficulty":"hard","question":"The mean of 6 observations is 20. If five observations are 12, 18, 22, 25, 28, find the sixth observation.","options":{"A":"15","B":"18","C":"20","D":"25"},"correct_answer":"A"},
    {"id":137,"difficulty":"hard","question":"If the median of 7 observations arranged in order is 24, which position does it occupy?","options":{"A":"3rd","B":"4th","C":"5th","D":"6th"},"correct_answer":"B"},
    {"id":138,"difficulty":"hard","question":"The mean of numbers 5, x, 15 is 10. Find x.","options":{"A":"5","B":"10","C":"15","D":"20"},"correct_answer":"B"},
    {"id":139,"difficulty":"hard","question":"Data has mode 18 occurring 6 times. Which value represents mode?","options":{"A":"Most frequent","B":"Middle value","C":"Average","D":"Difference"},"correct_answer":"A"},
    {"id":140,"difficulty":"hard","question":"If total frequency is 40 and mean is 25, what is the sum of observations?","options":{"A":"900","B":"950","C":"1000","D":"1050"},"correct_answer":"C"},
    {"id":141,"difficulty":"hard","question":"In a pie chart, if one sector is 72°, what percentage does it represent?","options":{"A":"15%","B":"18%","C":"20%","D":"25%"},"correct_answer":"C"},
    {"id":142,"difficulty":"hard","question":"If range of data is 30 and maximum value is 75, what is minimum value?","options":{"A":"35","B":"40","C":"45","D":"50"},"correct_answer":"C"},
    {"id":143,"difficulty":"hard","question":"Which measure is most affected by extreme values?","options":{"A":"Mean","B":"Median","C":"Mode","D":"Range"},"correct_answer":"A"},
    {"id":144,"difficulty":"hard","question":"If median = mean = mode, the data is:","options":{"A":"Skewed","B":"Irregular","C":"Symmetrical","D":"Random"},"correct_answer":"C"},
    {"id":145,"difficulty":"hard","question":"Find the mean of first 10 natural numbers.","options":{"A":"4.5","B":"5","C":"5.5","D":"6"},"correct_answer":"C"},
    {"id":146,"difficulty":"hard","question":"The mode of data 3, 5, 7, 9 is:","options":{"A":"3","B":"5","C":"7","D":"No mode"},"correct_answer":"D"},
    {"id":147,"difficulty":"hard","question":"If frequencies of values are equal, which measure is preferred?","options":{"A":"Mode","B":"Mean","C":"Median","D":"Range"},"correct_answer":"B"},
    {"id":148,"difficulty":"hard","question":"If a pie chart shows a category of 144°, what fraction is it?","options":{"A":"1/2","B":"2/5","C":"3/10","D":"4/9"},"correct_answer":"B"},
    {"id":149,"difficulty":"hard","question":"The sum of observations is 420 and total frequency is 21. Find the mean.","options":{"A":"18","B":"19","C":"20","D":"21"},"correct_answer":"C"},
    {"id":150,"difficulty":"hard","question":"Which measure gives the middle value when data is arranged?","options":{"A":"Mean","B":"Mode","C":"Median","D":"Range"},"correct_answer":"C"}
]
}