Question

30 children were asked about the number of hours they watched TV programmes last week. The results are recorded as under: Number of hours 0-5, 5-10, 10-15, 15-20; Frequency 8, 16, 4, 2. Can we say that the number of children who watched TV for 10 or more hours a week is 22? Justify your answer.

Prepare a continuous grouped frequency distribution from the following data: Mid-point 5, 15, 25, 35, 45; Frequency 4, 8, 13, 12, 6. Also find the size of class intervals.

Two sections of Class IX having 30 students each appeared for mathematics olympiad. The marks obtained by them are shown below: 46, 31, 74, 68, 42, 54, 14, 61, 83, 48, 37, 26, 8, 64, 57, 93, 72, 53, 59, 38, 16, 88, 75, 56, 46, 66, 45, 61, 54, 27, 27, 44, 63, 58, 43, 81, 64, 67, 36, 49, 50, 76, 38, 47, 55, 77, 62, 53, 40, 71, 60, 58, 45, 42, 34, 46, 40, 59, 42, 29. Construct a group frequency distribution of the data above using the classes 0-9, 10-19 etc., and hence find the number of students who secured more than 49 marks.

The following are the marks (out of 100) of 60 students in mathematics. 16, 13, 5, 80, 86, 7, 51, 48, 24, 56, 70, 19, 61, 17, 16, 36, 34, 42, 34, 35, 72, 55, 75, 31, 52, 28, 72, 97, 74, 45, 62, 68, 86, 35, 85, 36, 81, 75, 55, 26, 95, 31, 7, 78, 92, 62, 52, 56, 15, 63, 25, 36, 54, 44, 47, 27, 72, 17, 4, 30. Construct a grouped frequency distribution table with width 10 of each class starting from 0 - 9.