NDA 2018 Maths · Mathematics · Statistics · easy

If a constant c is added to every observation, the mean increases by c. 2. If a constant c is added to every observation, the variance increases by c.

Single correct option

Consider the following statements:
1. If a constant

c

is added to every observation, the mean increases by

c

.
2. If a constant

c

is added to every observation, the variance increases by

c

.
Which of the statements given above is/are correct?

A. 1 only
B. 2 only
C. Both 1 and 2
D. Neither 1 nor 2

Show answer and solution

Answer: (A) 1 only

Adding

c

to each value shifts the mean by

c

: statement 1 is true. Deviations from the mean are unchanged, so the variance and standard deviation do not change at all: statement 2 is false. Hence 1 only.

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Original question written in the NDA 2018 Maths pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake