Statistics Class 11 MCQs Questions with Answers

1. The mean of a group of 100 observations was found to be 20. Later on, it was found that three observations were incorrect, which was recorded as 21, 21 and 18. Then the mean if the incorrect observations are omitted is

2. Which one is measure of dispersion method

3. If the mean of the following data is 20.6, then the value of p is
x = 10  15   p   25  35
f =   3   10  25   7    5

4. If a variable takes discrete values x + 4, x – 7/2, x – 5/2, x – 3, x – 2, x + 1/2, x – 1/2, x + 5 (x > 0), then the median is

5. Let x₁, x₂, x₃, ……… , x_n, be n observations and X be the arithmetic mean. Then formula for the standard deviation is given by

6. Varience is independent of change of

7. The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n is

8.  For a moderately skewed distribution, quartile deviation and the standard deviation are related by

9.  The two lines of regression are 2x – 7y + 6 = 0 and 7x – 2y +1 = 0. What is correlation coefficient between x and y ?

10. If one of the observation is zero then geometric mean is

11. The mean of 5 observations is 4.4 and their variance is 8.24. If three observations are 1,2 and 6, the other two observations are

12. If the mean of first n natural numbers is 5n/9, then n =

13. If the varience of the data is 121 then the standard deviation of the data is

14. If covariance between two variables is 0, then the correlation coefficient between them is

15. The coefficient of correlation r satisfies