Mathematics (NDA/NA SOLVED PAPER 2021-I) (101 to 120)

Total Questions: 20

1. Consider the following measures of central tendency for a set of N numbers:

1. Arithmetic mean
2. Geometric mean
Which of the above uses/use all the data?

Correct Answer: (c) Both 1 and 2
Solution:

2. The numbers of Science, Arts and Commerce graduates working in a company are 30, 70 and 50 respectively. If these figures are represented by a pie chart, then what is the angle corresponding to Science graduates?

Correct Answer: (b) 72°
Solution:

3. For a histogram based on a frequency distribution with unequal class intervals, the frequency of a class should be proportional to

Correct Answer: (b) the area of the rectangle
Solution:(b)

4. The coefficient of correlation is independent of

Correct Answer: (c) both change of scale and change of origin
Solution:(c)

5. The following table gives the frequency distribution of number of peas per pea pod of 198 pods:

Number of peas (x)Frequency (f)
14
233
376
450
526
68
71

What is the median of this distribution?

Correct Answer: (a) 3
Solution:
Number of PeasFrequencyCumulative Frequency 
144
23337
376113
450163
526189
68197
71198

Group of S.D. = 198/2 = 99
S.D. = 3.

6. If M is the mean of n observations x₁ - k, x₂ - k, x₃ - k,_____, xₙ- k, where k is any real number, then what is the mean of x₁, x₂, x₃,_______,xₙ?

Correct Answer: (b) M + k
Solution:

7. What is the sum of deviations of the variate values 73, 85, 92, 105, 120 from their mean?

Correct Answer: (c) 0
Solution:

8. Let x be the HM and y be the GM of two positive numbers m and n. If 5x = 4y then which one of the following is correct?

Correct Answer: (d) m = 4n
Solution:

9. If the mean of a frequency distribution is 100 and the coefficient of variation is 45%, then what is the value of the variance?

Correct Answer: (a) 2025
Solution:

10. Let two events A and B be such that P(A) = L and P(B) = M. Which one of the following is correct?

Correct Answer: (c)
Solution: