{
  "title": "Frequency Tables (Data Handling) - Grade 8 CBSE",
  "total_questions": 100,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "What is a frequency in statistics?", "options": {"A": "The average of data", "B": "The number of times a value occurs", "C": "The highest value", "D": "The difference between values"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "What is a frequency distribution table?", "options": {"A": "A table showing data in alphabetical order", "B": "A table showing values and their frequencies", "C": "A table of mathematical formulas", "D": "A table of random numbers"}, "correct_answer": "B"},
    {"id": 3, "difficulty": "easy", "question": "In a survey of favourite colours, if 'Blue' is chosen 12 times, what is its frequency?", "options": {"A": "The colour blue", "B": "12", "C": "The number of people surveyed", "D": "The average"}, "correct_answer": "B"},
    {"id": 4, "difficulty": "easy", "question": "What is the tally mark for the number 5?", "options": {"A": "||||", "B": "|||| |", "C": "|||", "D": "|||| ||"}, "correct_answer": "B"},
    {"id": 5, "difficulty": "easy", "question": "How is the number 3 represented in tally marks?", "options": {"A": "|||", "B": "||||", "C": "|", "D": "||"}, "correct_answer": "A"},
    {"id": 6, "difficulty": "easy", "question": "If we have data: 2, 3, 2, 4, 3, 2, what is the frequency of 2?", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "C"},
    {"id": 7, "difficulty": "easy", "question": "What does the 'sum of frequencies' equal?", "options": {"A": "The largest value", "B": "The total number of observations", "C": "The average value", "D": "The range"}, "correct_answer": "B"},
    {"id": 8, "difficulty": "easy", "question": "Which column in a frequency table shows the count?", "options": {"A": "Data column", "B": "Tally column", "C": "Frequency column", "D": "Both B and C"}, "correct_answer": "D"},
    {"id": 9, "difficulty": "easy", "question": "Tally marks are grouped in sets of ___ for easy counting.", "options": {"A": "2", "B": "3", "C": "4", "D": "5"}, "correct_answer": "D"},
    {"id": 10, "difficulty": "easy", "question": "If the frequency of 'Apple' is 8 and 'Orange' is 5, how many more people chose Apple?", "options": {"A": "3", "B": "5", "C": "8", "D": "13"}, "correct_answer": "A"},
    {"id": 11, "difficulty": "easy", "question": "What is the first step in making a frequency table?", "options": {"A": "Draw tally marks", "B": "List the distinct values", "C": "Calculate the mean", "D": "Draw a graph"}, "correct_answer": "B"},
    {"id": 12, "difficulty": "easy", "question": "For the data: A, B, A, C, B, A, what is the frequency of B?", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "B"},
    {"id": 13, "difficulty": "easy", "question": "A frequency table is used to ___.", "options": {"A": "organize raw data", "B": "draw a pie chart directly", "C": "find the median without calculation", "D": "change the data values"}, "correct_answer": "A"},
    {"id": 14, "difficulty": "easy", "question": "If total observations are 20, the sum of all frequencies should be ___.", "options": {"A": "10", "B": "20", "C": "30", "D": "40"}, "correct_answer": "B"},
    {"id": 15, "difficulty": "easy", "question": "Which is NOT a part of a basic frequency table?", "options": {"A": "Class interval", "B": "Data values", "C": "Tally marks", "D": "Frequency"}, "correct_answer": "A"},
    {"id": 16, "difficulty": "easy", "question": "The data value with the highest frequency is called the ___.", "options": {"A": "mean", "B": "median", "C": "mode", "D": "range"}, "correct_answer": "C"},
    {"id": 17, "difficulty": "easy", "question": "From a frequency table, we can easily find the ___.", "options": {"A": "mode", "B": "mean", "C": "range", "D": "All of these"}, "correct_answer": "A"},
    {"id": 18, "difficulty": "easy", "question": "Tally marks for 7 are ___.", "options": {"A": "|||| ||", "B": "|||| |", "C": "|||| |||", "D": "||| ||"}, "correct_answer": "A"},
    {"id": 19, "difficulty": "easy", "question": "If frequency of score 10 is 0, it means ___.", "options": {"A": "10 is the highest score", "B": "No one scored 10", "C": "Everyone scored 10", "D": "10 is the average"}, "correct_answer": "B"},
    {"id": 20, "difficulty": "easy", "question": "In a class of 30, a frequency table shows sum of frequencies as 30. This is ___.", "options": {"A": "correct", "B": "incorrect", "C": "possible only for large data", "D": "not necessary"}, "correct_answer": "A"},

    {"id": 21, "difficulty": "medium", "question": "Given data: 5, 6, 5, 7, 6, 5, 8, 6, 5. What is the frequency of 6?", "options": {"A": "2", "B": "3", "C": "4", "D": "5"}, "correct_answer": "B"},
    {"id": 22, "difficulty": "medium", "question": "In a survey of 50 people, the frequency of 'Yes' is 30. What is the frequency of 'No' if only these two options exist?", "options": {"A": "10", "B": "20", "C": "30", "D": "40"}, "correct_answer": "B"},
    {"id": 23, "difficulty": "medium", "question": "What is the range of the data represented in a frequency table with values 2(f=3), 4(f=5), 6(f=2)?", "options": {"A": "2", "B": "4", "C": "6", "D": "8"}, "correct_answer": "B"},
    {"id": 24, "difficulty": "medium", "question": "If the mode of a data set is 15, and its frequency is 7, which statement is true?", "options": {"A": "15 occurs 7 times", "B": "15 is the average", "C": "15 is the smallest", "D": "15 is the largest"}, "correct_answer": "A"},
    {"id": 25, "difficulty": "medium", "question": "From a frequency table: Value 10 (f=4), 20 (f=6), 30 (f=5). What is the total number of observations?", "options": {"A": "3", "B": "15", "C": "60", "D": "120"}, "correct_answer": "B"},
    {"id": 26, "difficulty": "medium", "question": "What is the mean of the data from the frequency table: 5(f=2), 10(f=3), 15(f=1)?", "options": {"A": "8", "B": "8.33", "C": "9", "D": "10"}, "correct_answer": "B"},
    {"id": 27, "difficulty": "medium", "question": "A frequency table shows class intervals. What is this table called?", "options": {"A": "Simple frequency table", "B": "Grouped frequency table", "C": "Cumulative frequency table", "D": "Relative frequency table"}, "correct_answer": "B"},
    {"id": 28, "difficulty": "medium", "question": "Why do we use grouped frequency tables?", "options": {"A": "To reduce number of rows", "B": "For continuous data or large range", "C": "To make it colorful", "D": "To find the mode faster"}, "correct_answer": "B"},
    {"id": 29, "difficulty": "medium", "question": "In a grouped frequency table, the intervals 0-10, 10-20, 20-30 are used. In which interval would the value 10 fall?", "options": {"A": "0-10", "B": "10-20", "C": "It can be in either", "D": "Nowhere"}, "correct_answer": "B"},
    {"id": 30, "difficulty": "medium", "question": "What is the class size of intervals 10-20, 20-30, 30-40?", "options": {"A": "5", "B": "10", "C": "15", "D": "20"}, "correct_answer": "B"},
    {"id": 31, "difficulty": "medium", "question": "The midpoint of class 20-30 is ___.", "options": {"A": "20", "B": "25", "C": "30", "D": "50"}, "correct_answer": "B"},
    {"id": 32, "difficulty": "medium", "question": "What is the cumulative frequency?", "options": {"A": "Frequency of the current class", "B": "Sum of frequencies of all previous classes including current", "C": "Difference between frequencies", "D": "Average of frequencies"}, "correct_answer": "B"},
    {"id": 33, "difficulty": "medium", "question": "If cumulative frequency up to class 30-40 is 45 and frequency of class 30-40 is 10, what is the cumulative frequency up to previous class?", "options": {"A": "35", "B": "45", "C": "55", "D": "10"}, "correct_answer": "A"},
    {"id": 34, "difficulty": "medium", "question": "For a grouped data, the modal class is the class with the ___.", "options": {"A": "highest frequency", "B": "lowest frequency", "C": "largest class size", "D": "smallest midpoint"}, "correct_answer": "A"},
    {"id": 35, "difficulty": "medium", "question": "In a frequency table, the relative frequency is calculated as ___.", "options": {"A": "frequency × total", "B": "frequency / total frequency", "C": "total frequency / frequency", "D": "frequency - mean"}, "correct_answer": "B"},
    {"id": 36, "difficulty": "medium", "question": "If total frequency is 50 and frequency of a class is 5, its relative frequency is ___.", "options": {"A": "0.05", "B": "0.1", "C": "0.5", "D": "5"}, "correct_answer": "B"},
    {"id": 37, "difficulty": "medium", "question": "What is the upper class limit of the interval 15-25?", "options": {"A": "15", "B": "20", "C": "25", "D": "40"}, "correct_answer": "C"},
    {"id": 38, "difficulty": "medium", "question": "The class mark of interval 50-60 is ___.", "options": {"A": "50", "B": "55", "C": "60", "D": "110"}, "correct_answer": "B"},
    {"id": 39, "difficulty": "medium", "question": "In a frequency table with intervals 0-9, 10-19, etc., the class size is ___.", "options": {"A": "9", "B": "10", "C": "9.5", "D": "10.5"}, "correct_answer": "B"},
    {"id": 40, "difficulty": "medium", "question": "If the frequency of class 20-29 is 12, and class size is 10, what is the frequency density?", "options": {"A": "0.83", "B": "1.2", "C": "2.4", "D": "12"}, "correct_answer": "B"},
    {"id": 41, "difficulty": "medium", "question": "Data: 12, 15, 12, 18, 15, 12, 20. Which frequency table is correct?", "options": {"A": "12(2),15(2),18(1),20(1)", "B": "12(3),15(2),18(1),20(1)", "C": "12(3),15(2),18(2),20(1)", "D": "12(1),15(3),18(1),20(1)"}, "correct_answer": "B"},
    {"id": 42, "difficulty": "medium", "question": "From a frequency table, the median is the value where cumulative frequency reaches ___.", "options": {"A": "n/2", "B": "n/3", "C": "n", "D": "2n"}, "correct_answer": "A"},
    {"id": 43, "difficulty": "medium", "question": "The sum of relative frequencies for all classes always equals ___.", "options": {"A": "0", "B": "0.5", "C": "1", "D": "100"}, "correct_answer": "C"},
    {"id": 44, "difficulty": "medium", "question": "In a grouped table, if the class intervals are not continuous, we make them continuous by using ___", "options": {"A": "class marks", "B": "class limits", "C": "class boundaries", "D": "tally marks"}, "correct_answer": "C"},
    {"id": 45, "difficulty": "medium", "question": "For intervals 10-19, 20-29, the class boundaries for first class are ___.", "options": {"A": "9.5-19.5", "B": "10-19", "C": "10-20", "D": "9-19"}, "correct_answer": "A"},
    {"id": 46, "difficulty": "medium", "question": "What is the frequency density used for?", "options": {"A": "To compare classes of different widths", "B": "To find the total frequency", "C": "To calculate mean", "D": "To draw a pie chart"}, "correct_answer": "A"},
    {"id": 47, "difficulty": "medium", "question": "If a class interval is 30-40, its lower class limit is ___.", "options": {"A": "30", "B": "35", "C": "40", "D": "70"}, "correct_answer": "A"},
    {"id": 48, "difficulty": "medium", "question": "A student records marks as intervals 0-10, 10-20, etc. If a score is exactly 20, in which interval should it be placed?", "options": {"A": "10-20", "B": "20-30", "C": "Both", "D": "None"}, "correct_answer": "B"},
    {"id": 49, "difficulty": "medium", "question": "The cumulative frequency of the last class equals ___.", "options": {"A": "frequency of last class", "B": "total frequency", "C": "zero", "D": "frequency of first class"}, "correct_answer": "B"},
    {"id": 50, "difficulty": "medium", "question": "Which measure cannot be found exactly from a grouped frequency table?", "options": {"A": "Modal class", "B": "Mean", "C": "Exact median", "D": "Range"}, "correct_answer": "C"},
    {"id": 51, "difficulty": "medium", "question": "For data: 5,7,5,9,7,5, the frequency of 7 is ___.", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "B"},
    {"id": 52, "difficulty": "medium", "question": "If the total frequency is 120, and relative frequency of a class is 0.25, its frequency is ___.", "options": {"A": "25", "B": "30", "C": "40", "D": "48"}, "correct_answer": "B"},
    {"id": 53, "difficulty": "medium", "question": "What is the class size if class boundaries are 12.5-17.5?", "options": {"A": "5", "B": "6", "C": "12.5", "D": "17.5"}, "correct_answer": "A"},
    {"id": 54, "difficulty": "medium", "question": "In a frequency distribution, the classes should be ___.", "options": {"A": "mutually exclusive", "B": "overlapping", "C": "of different sizes", "D": "in descending order"}, "correct_answer": "A"},
    {"id": 55, "difficulty": "medium", "question": "The difference between the upper and lower class limits is the ___.", "options": {"A": "class frequency", "B": "class size", "C": "class mark", "D": "cumulative frequency"}, "correct_answer": "B"},
    {"id": 56, "difficulty": "medium", "question": "Given intervals 0-5, 5-10, 10-15, which value is not included properly?", "options": {"A": "2", "B": "5", "C": "10", "D": "12"}, "correct_answer": "B"},
    {"id": 57, "difficulty": "medium", "question": "To find the median from a grouped table, we use ___", "options": {"A": "modal class", "B": "cumulative frequency", "C": "class marks", "D": "frequency density"}, "correct_answer": "B"},
    {"id": 58, "difficulty": "medium", "question": "If a class interval is written as 10-20, 20-30, it is called ___ classification.", "options": {"A": "exclusive", "B": "inclusive", "C": "continuous", "D": "discrete"}, "correct_answer": "A"},
    {"id": 59, "difficulty": "medium", "question": "A 'less than' cumulative frequency table shows ___.", "options": {"A": "frequency less than upper limits", "B": "frequency greater than lower limits", "C": "frequency of each class", "D": "relative frequency"}, "correct_answer": "A"},
    {"id": 60, "difficulty": "medium", "question": "For a data set, the sum of frequencies is 45. The median is the value of the ___ observation.", "options": {"A": "20th", "B": "22.5th", "C": "23rd", "D": "22nd"}, "correct_answer": "C"},
    {"id": 61, "difficulty": "medium", "question": "Which of these is necessary for a grouped frequency table?", "options": {"A": "Class intervals", "B": "Tally marks", "C": "Cumulative frequency", "D": "All of these"}, "correct_answer": "A"},
    {"id": 62, "difficulty": "medium", "question": "If the class mark is 25 and class size is 10, the class interval is ___.", "options": {"A": "20-30", "B": "25-35", "C": "15-25", "D": "20-25"}, "correct_answer": "A"},
    {"id": 63, "difficulty": "medium", "question": "Relative frequency is also expressed as ___", "options": {"A": "percentage", "B": "angle", "C": "ratio", "D": "All of these"}, "correct_answer": "D"},
    {"id": 64, "difficulty": "medium", "question": "If the frequency of a class is zero, we usually ___.", "options": {"A": "omit the class", "B": "keep it to show no data", "C": "merge it with next class", "D": "assign it a frequency 1"}, "correct_answer": "B"},
    {"id": 65, "difficulty": "medium", "question": "In a survey, 'sometimes' has frequency 18, 'always' 12, 'never' 10. What is the total number of responses?", "options": {"A": "30", "B": "40", "C": "50", "D": "60"}, "correct_answer": "B"},
    {"id": 66, "difficulty": "medium", "question": "The class boundaries for the interval 15-20 are ___.", "options": {"A": "15 and 20", "B": "14.5 and 20.5", "C": "15.5 and 19.5", "D": "10 and 25"}, "correct_answer": "B"},
    {"id": 67, "difficulty": "medium", "question": "For drawing a histogram, we need a ___ frequency table.", "options": {"A": "simple", "B": "grouped", "C": "cumulative", "D": "relative"}, "correct_answer": "B"},
    {"id": 68, "difficulty": "medium", "question": "If a class interval is 0-10, 10-20, etc., and a value is 10.0, it belongs to class ___.", "options": {"A": "0-10", "B": "10-20", "C": "both", "D": "none"}, "correct_answer": "B"},
    {"id": 69, "difficulty": "medium", "question": "The median class is the class where cumulative frequency first exceeds ___.", "options": {"A": "n/4", "B": "n/2", "C": "3n/4", "D": "n"}, "correct_answer": "B"},
    {"id": 70, "difficulty": "medium", "question": "What is the mode of the data represented by frequency table: 2(f=4), 3(f=7), 4(f=7), 5(f=2)?", "options": {"A": "3", "B": "4", "C": "3 and 4", "D": "7"}, "correct_answer": "C"},
    {"id": 71, "difficulty": "medium", "question": "In a frequency polygon, points are plotted using ___ and ___.", "options": {"A": "class marks, frequencies", "B": "class limits, cumulative frequencies", "C": "class boundaries, relative frequencies", "D": "lower limits, frequencies"}, "correct_answer": "A"},
    {"id": 72, "difficulty": "medium", "question": "If the cumulative frequency before a class is 30 and frequency of the class is 15, the cumulative frequency after that class is ___.", "options": {"A": "15", "B": "30", "C": "45", "D": "60"}, "correct_answer": "C"},
    {"id": 73, "difficulty": "medium", "question": "A 'more than' cumulative frequency table is constructed using ___ limits.", "options": {"A": "upper", "B": "lower", "C": "class marks", "D": "class boundaries"}, "correct_answer": "B"},
    {"id": 74, "difficulty": "medium", "question": "For the class 25-30, the lower class boundary is ___.", "options": {"A": "25", "B": "27.5", "C": "24.5", "D": "30.5"}, "correct_answer": "C"},
    {"id": 75, "difficulty": "medium", "question": "If the total frequency is N, the median is the average of the (N/2)th and (N/2 + 1)th values when N is ___.", "options": {"A": "odd", "B": "even", "C": "prime", "D": "any number"}, "correct_answer": "B"},
    {"id": 76, "difficulty": "medium", "question": "Which graph is based on cumulative frequency?", "options": {"A": "Ogive", "B": "Histogram", "C": "Frequency polygon", "D": "Bar graph"}, "correct_answer": "A"},
    {"id": 77, "difficulty": "medium", "question": "The range of data: 10(f=3), 20(f=5), 30(f=2) is ___.", "options": {"A": "10", "B": "20", "C": "30", "D": "40"}, "correct_answer": "B"},
    {"id": 78, "difficulty": "medium", "question": "The class interval with the highest frequency density has the ___", "options": {"A": "highest frequency", "B": "highest frequency per unit width", "C": "largest class size", "D": "smallest class mark"}, "correct_answer": "B"},
    {"id": 79, "difficulty": "medium", "question": "To find the mean from a grouped table, we assume all values in a class are equal to the ___.", "options": {"A": "lower limit", "B": "upper limit", "C": "class mark", "D": "frequency"}, "correct_answer": "C"},
    {"id": 80, "difficulty": "medium", "question": "If the class intervals are 0-100, 100-200, etc., the class size is ___.", "options": {"A": "50", "B": "100", "C": "150", "D": "200"}, "correct_answer": "B"},

    {"id": 81, "difficulty": "hard", "question": "In a grouped frequency table, if the class intervals are 10-14, 15-19, 20-24, what is the class size?", "options": {"A": "4", "B": "5", "C": "10", "D": "14"}, "correct_answer": "B"},
    {"id": 82, "difficulty": "hard", "question": "For a data set with 100 observations, the cumulative frequency table shows CF up to class 30-40 is 55 and up to class 40-50 is 80. What is the frequency of class 40-50?", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 83, "difficulty": "hard", "question": "The mean of a grouped data is calculated as 42.5. If sum of (f × x) is 850, what is the total frequency?", "options": {"A": "15", "B": "20", "C": "25", "D": "30"}, "correct_answer": "B"},
    {"id": 84, "difficulty": "hard", "question": "In a 'less than' ogive, the point (30, 45) means that ___", "options": {"A": "45 observations are less than 30", "B": "30 observations are less than 45", "C": "frequency of class up to 30 is 45", "D": "45 observations are more than 30"}, "correct_answer": "A"},
    {"id": 85, "difficulty": "hard", "question": "If the median of a grouped data lies in class 50-60 with cumulative frequency before it = 40, frequency of class = 20, and total frequency = 100, what is the median value? (Use formula)", "options": {"A": "52.5", "B": "55", "C": "57.5", "D": "60"}, "correct_answer": "B"},
    {"id": 86, "difficulty": "hard", "question": "The modal class of a distribution is 70-80. If the frequencies of preceding and following classes are 12 and 18 respectively, and frequency of modal class is 25, what is the mode? (Use formula)", "options": {"A": "72", "B": "74", "C": "76", "D": "78"}, "correct_answer": "C"},
    {"id": 87, "difficulty": "hard", "question": "For a grouped data, the class marks are 15, 25, 35, 45 and frequencies are 4, 6, 8, 2. What is the approximate mean?", "options": {"A": "27.5", "B": "28", "C": "29", "D": "30"}, "correct_answer": "C"},
    {"id": 88, "difficulty": "hard", "question": "In a cumulative frequency distribution, the last value should always be equal to ___.", "options": {"A": "frequency of last class", "B": "total frequency", "C": "class size", "D": "zero"}, "correct_answer": "B"},
    {"id": 89, "difficulty": "hard", "question": "A frequency distribution has classes 0-10, 10-20, etc. A value 19.99 belongs to which class?", "options": {"A": "0-10", "B": "10-20", "C": "20-30", "D": "Cannot say"}, "correct_answer": "B"},
    {"id": 90, "difficulty": "hard", "question": "If the relative frequency of a class is 0.2 and total observations are 150, the class frequency is ___.", "options": {"A": "20", "B": "30", "C": "75", "D": "120"}, "correct_answer": "B"},
    {"id": 91, "difficulty": "hard", "question": "The sum of deviations of observations from their mean is zero. For grouped data, sum of f_i*(x_i - mean) = ?", "options": {"A": "0", "B": "1", "C": "mean", "D": "total frequency"}, "correct_answer": "A"},
    {"id": 92, "difficulty": "hard", "question": "In a grouped table, if the class intervals are of unequal widths, which graph is appropriate?", "options": {"A": "Histogram with frequency density", "B": "Bar graph", "C": "Frequency polygon", "D": "Pie chart"}, "correct_answer": "A"},
    {"id": 93, "difficulty": "hard", "question": "For a symmetrical distribution, the mean, median, and mode are related as ___.", "options": {"A": "mean = median = mode", "B": "mean > median > mode", "C": "mean < median < mode", "D": "no relation"}, "correct_answer": "A"},
    {"id": 94, "difficulty": "hard", "question": "If the class boundaries are 29.5-39.5, the class interval in inclusive form is ___.", "options": {"A": "29-39", "B": "30-39", "C": "30-40", "D": "29-40"}, "correct_answer": "B"},
    {"id": 95, "difficulty": "hard", "question": "The median of a grouped data is calculated by interpolating within the median class using the formula. This assumes data are ___ distributed within the class.", "options": {"A": "uniformly", "B": "randomly", "C": "normally", "D": "exponentially"}, "correct_answer": "A"},
    {"id": 96, "difficulty": "hard", "question": "If the cumulative frequency just greater than N/2 is 65 and corresponding class is 40-50, and cumulative frequency before it is 40, frequency of class is 25, N=100, median is?", "options": {"A": "42", "B": "44", "C": "46", "D": "48"}, "correct_answer": "C"},
    {"id": 97, "difficulty": "hard", "question": "In a frequency table, if each frequency is multiplied by 2, what happens to the mean?", "options": {"A": "Doubles", "B": "Halves", "C": "Remains same", "D": "Cannot say"}, "correct_answer": "C"},
    {"id": 98, "difficulty": "hard", "question": "For a grouped data, the variance is calculated using class marks and frequencies. If each class mark is increased by 5, the variance ___.", "options": {"A": "increases by 5", "B": "decreases by 5", "C": "remains same", "D": "increases by 25"}, "correct_answer": "C"},
    {"id": 99, "difficulty": "hard", "question": "A data set has 200 observations. The cumulative frequency table shows that 60 observations are below 30 and 120 below 40. How many observations are between 30 and 40?", "options": {"A": "40", "B": "60", "C": "80", "D": "100"}, "correct_answer": "B"},
    {"id": 100, "difficulty": "hard", "question": "The mode of a grouped data is 35. If the class size is 10, and modal class is 30-40, with frequencies f0=12, f1=20, f2=15, the mode calculated by formula is ___.", "options": {"A": "33.33", "B": "35.56", "C": "36.67", "D": "37.78"}, "correct_answer": "B"}
  ]
}