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ASSIGNMENT, , CLASS X, STATISTICS, , 1. Find the mean of the following frequency distribution :, Class, Frequency, , 0-20 20-40 40-60 60-80 80-100, 15, , 18, , 21, , 29, , 17, , 2. Find the mean of the following frequency distribution :, Class Interval 10-30 30-50 50-70 70-90 90-110, Frequency, , 90, , 20, , 30, , 20, , 40, , 3. Find the mean of the following frequency distribution :, Class Interval, , 0-20 20-40 40-60 60-80 80-100 100-120, , Frequency, , 20, , 35, , 52, , 44, , 38, , 31, , 4. Find the mean of the following frequency distribution :, Class, , 4-8 8-12 12-16 16-20 20-24 24-28 28-32 32-36, , No. of students, , 2, , 12, , 15, , 25, , 18, , 12, , 13, , 3, , 5. Find the mean of the following frequency distribution :, Class Interval, , 0-50 50-100 100-150 150-200 200-250 250-300, , Frequency, , 17, , 35, , 43, , 40, , 21, , 24, , 6. Compute the mean for the following data :, Marks (less than ) 10 20 30 40 50 60 70, No. of students, , 80, , 12 19 35 47 58 65 84 100, , 7. Compute the mean for the following data :, Marks ( More than), No. of students, , 0, , 10 20 30 40 50, , 100 95 70 20, , 5, , 0, , 8. If the mean of the following distribution is 54, find the value of p :, Class, Frequency, , 0-20 20-40 40-60 60-80 80-100, 7, , p, , 10, , 9, , 13, , 9. If the mean of the distribution is 57.6 and the sum of its observations is 50, find the missing, frequencies f1 and f2., Class, Frequency, , 0-20 20-40 40-60 60-80 80-100 100-120, 7, , f1, , 12, , f2, , 8, , 5, , 10. The mean of the following frequency table is 50. But the frequencies f1 and f2 in class 20-40 and, 60-80 are missing. Find the missing frequencies., Class, Frequency, , 0-20 20-40 40-60 60-80 80-100 Total, 17, , f1, , 32, , f2, , 1, , 19, , 120

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11. Find the mode for the following distribution table :, Class Interval, Frequency, , 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80, 7, , 14, , 13, , 12, , 20, , 11, , 15, , 8, , 12. The following table shows the ages of the patients admitted in a hospital during a year :, Age (in years), No. of patients, , 5-15 15-25 25-35 35-45 45-55 55-65, 6, , 11, , 21, , 23, , 14, , 5, , Find the mode and the mean of the data given above. Compare and interpret the two measures of, central tendency., 13. Calculate the mode of the following distribution :, Marks, , 80-90 90-100 100-110 110-120 120-130 130-140 140-150, , No. of Students, , 18, , 27, , 48, , 39, , 12, , 6, , 16, , 14. The following table shows the marks obtained by 100 students of class X in a school during a, particular academic session. Find the mode of this distribution., Marks, No. of Students, Less than 10, 7, Less than 20, 21, Less than 30, 34, Less than 40, 46, Less than 50, 66, Less than 60, 77, Less than 70, 92, Less than 80, 100, 15. The mode of the following distribution is 43.75. Find the missing frequency p., Class Interval, Frequency, , 20-30 30-40 40-50 50-60 60-70, 25, , 47, , 62, , p, , 10, , 16. Find the median of the following frequency distribution :, Class Interval, Frequency, , 0-10 10-20 20-30 30-40 40-50 50-60, 5, , 3, , 10, , 6, , 4, , 2, , 17. Calculate the median for the following data :, Marks obtained (less than ) 10 20 30 40 50 60, No. of students, , 6, , 15, , 29, , 41 60 70, , 18. Calculate the median for the following data :, Marks obtained ( more than ) 150 140 130 120 110 100, No. of students, , 0, , 12, , 27, , 60, , 90, , 80, , 105 124 141 150, , 19. The median of the following distribution is 35, find the value of a and b., Class Interval, Frequency, , 0-10 10-20 20-30 30-40 40-50 50-60 60-70 Total, 10, , 20, , a, , 40, , 2, , b, , 25, , 15, , 170

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20. If the median of the following frequency distribution is 32.5, find the values of missing, frequencies a and b., Class Interval, , Frequency, , 0-10, , a, , 10-20, 20-30, , 5, 9, , 30-40, 40-50, , 12, b, , 50-60, , 3, , 60-70, Total, , 2, 40, , 21. Calculate the mean, the median and the mode of the following distribution :, Age (in years), , 12 13 14 15 16 17 18, , No. of Students, , 2, , 3, , 5, , 6, , 4, , 3, , 2, , 22. Find the mean and mode of the following data. Also, interpret your result., Class Interval 10-30 30-50 50-70 70-90 90-110 110-130 130-150, Frequency, , 3, , 2, , 5, , 4, , 7, , 5, , 4, , 23. Find the mode and median for the following data. Also interpret your answer., Class Interval 10-20 20-30 30-40 40-50 50-60 60-70 70-80, Frequency, , 7, , 4, , 6, , 10, , 9, , 8, , 6, , 24. Calculate mean, median and mode for the following distribution., Class Interval, , 0-10 10-20 20-30 30-40 40-50 50-60, , Frequency, , 2, , 6, , 9, , 7, , 4, , 2, , 25. Calculate the mode and median for the following data :, Class Interval, , 0-100 100-200 200-300 300-400 400-500 500-600, , Frequency, , 26, , 37, , 33, , 25, , 18, , 11, , 26. The following table shows the weights in gm of a sample of 100 potatoes taken from a large, consignment:, Weight, Frequency, , 50-60 60-70 70-80 80-90 90-100 100-110 110-120 120-130, 8, , 10, , 12, , 16, , 18, , 14, , 12, , 10, , Draw the cumulative frequency curve and from it determine the median weight of the potatoes., 27. For the following frequency distribution, draw both the types of cumulative frequency curve on, the same graph paper and hence find the median., Marks obtained, No. of students, , 50-60 60-70 70-80 80-90 90-100, 4, , 8, , 12, , 3, , 6, , 6

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28. Draw a ‘less than type’ cumulative frequency curve for the following data., Class interval, Frequency, , 0-5 5-10 10-15 15-20 20-25 25-30 30-35 35-40, 7, , 10, , 20, , 13, , 17, , 10, , 14, , 9, , Hence, estimate the median., 29. Marks scored by 400 students in an examination are as follows :, Marks, No. of Students, , 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100, 10, , 20, , 22, , 40, , 55, , 75, , 80, , 58, , 28, , 12, , Draw a ‘more than type’ cumulative frequency curve and from it determine the median., 30. The table given below shows the distribution of the daily wages, earned by 160 workers in a, building site:, Wages (in Rs.), No. of Workers, , 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80, 12, , 20, , 30, , 38, , 24, , 16, , 12, , 8, , Draw a cumulative frequency curve by using : (i) ‘less than type’ and (ii) ‘more than type’., Hence, estimate the median wages using graph., , ANSWERS, 1. 55, , 2. 50, , 3. 62.545, , 4. 19.92, , 7. 24, , 8. 11, , 9. f1= 8, f2 = 10, , 5. 148.61, , 6. 43, , 10. f1 = 28, f2 = 24 11. 44.705, , 12. mode = 36.81 years; mean = 35.37 years, , 13. 107, , 14. 44.7, , 15. 37, , 19. a = 35, b = 25, , 20. a = 3, b = 6, , 16. 27, , 17. 35, , 18. 116.67, , 21. Mean = 14.96, Median = 15, Mode = 15, 23. mode = 48 ; median = 48, , 22. mean = 87.3 (approx); Mode = 102, , 24. mean = 28.6, median = 27.7, mode = 26, , 25. mode = 173.3 (approx), median = 236.36 (approx), 26. 93 gm, , 27. 75, , 28. 20, , 29. 57.5, , 4, , 30. Rs. 34.73