The marks obtained in a test by students of a class are given below:
23, 2, 15, 38, 21, 19,24, 26
Scores of how many students are within a +2 / -2 range of the average score of the class?

Correct option is B

Given:

Student marks 23, 2, 15, 38, 21, 19,24, 26

Solution:

$$\text{Average} = \frac{23 + 2 + 15 + 38 + 21 + 19 + 24 + 26}{8} = 21$$​​

$$Range \ \ 21 - 2 = 19 \quad \text{to} \quad 21 + 2 = 23$$

$$Range \ \ \ 21 - 2 = 19 \quad \text{to} \quad 21 + 2 = 23$$​​

3 students have scores within the +2 / -2 range of the average.