21. Five soldiers visit a rifle range for two consecutive weeks and their scores were recorded as follows:


The appropriate test that should be applied to test if there is any significant difference in their
performance based on scores is:
(a) Z‐ test for difference of means
(b) t ‐test for difference of means with equal variances
(c) Paired t‐test
(d) t ‐test for difference of means with unequal variances

Answer: (c)

22. The median of the distribution given below is 14.4.
If the total frequency is 20, then the values of x and y respectively are:
(a) 2, 4
(b) 3, 4
(c) 4, 6
(d) 5, 6

Answer: (c)

23. The following data give the mean and variance of the wages of the men working in three firms A, B and C:
(a) A
(b) B
(c) C
(d) Cannot be determined

Answer: (c)

24.
(a) Y = 3.2X + 58
(b) X = 3.2Y + 58
(c) X = 0.2Y - 8
(d) Y = 0.2X - 8

Answer: (a)

25.
(a) 3 and 13
(b) 2.5 and 3
(c) 13 and 2.5
(d) 2.5 and 13

Answer: (d)

26. The following data are given for two series:

The value of variance of combined series is:
(a) 14
(b) 16
(c) 17
(d) 19

Answer: (d)

27.
The first three moments about origin of a frequency distribution are
(a) Negatively skewed
(b) Symmetric
(c) Positively skewed
(d) Cannot be determined from the data

Answer: (b)

28.
Then the value of Karl Pearson’s correlation coefficient is:
(a) 0.4
(b) 0.5
(c) 0.6
(d) 0.7

Answer: (c)

29. For a continuous frequency distribution, consider the following statements:
1. Median can be located graphically using less than cumulative frequency curve.
2. Mode can be located graphically using the histogram.

Which of the above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c)

30. If Y = 3.2X + 58 and X = 0.2Y ‐ 8 are the lines of regression of Y on X and X on Y respectively, then the value of correlation coefficient between X and Y is:
(a) 0.6
(b) 0.7
(c) 0.8
(d) 0.9

Answer: (c)