Statistics-Important Questions

1.   The mean of 100 observations is 50. If one of the observation which was 50 is replaced by 150 then what will be the resulting mean?

2.   There are 50 numbers. Each number is subtracted from 53 and the mean of the numbers so obtained is found to be –3.5. What is the mean of given numbers?

3.   What is the mean of first 10 natural numbers?

4.   The mean of 10, 15, x, 5, 15 is 15. What is the value of x?

5.   In the frequency distribution.

        Class intervals                Frequencies

        0 –10                                           5

        10 – 20                                       15

        20 – 30                                       10

        30 – 40                                       2

        40 – 50                                       3

        What is the cumulative frequency corresponding to class 40 – 50?

6.   What is the median of the data 10, 16, 7, 9, 8, 4 and 12?

7.   What is the mode of the observations 11, 8, 10, 8, 15, 6, 7, 8, 12, 7 and 9?

8.   What is mode of the data 14, 20, 19, 14, 15, 16, 15, 14, 15, 18, 19, 14, 15, 18, 15?

9.   What is median of the following numbers: 4, 3, 4, 5, 12, 7, 7, 6, 7?

10.   What is the median of the data 78, 56, 22, 34, 45, 54, 39, 68, 54, 84?

11.   In the class intervals 10–20, 20–30, the number 20 is included in which of the following?

        (a) 10-20                                                (b) 20-30

        (c) both the intervals                        (d) none of these intervals

12.   The width of each of five continuous classes in a frequency distribution is 5 and the lower class limit of the lowest class is 10. What is the upper class limit of the highest class?