NTA Abhyas JEE Main2020MathematicsStatisticsPractice
Coefficient of variation of two distributions are 60 % and 75 % , and their standard deviation are 18 and 15 respectively, then their arithmetic means respectively are
Options
- A30 , 30
- B30 , 20
- C20 , 30
- D20 , 20
Correct answer
B. 30 , 20
Step-by-step solution
Given, C V 1 = 60 , C V 2 = 75 , σ 1 = 18 and σ 2 = 15 Let x - 1 and x - 2 be the means of 1 s t and 2 n d distribution respectively. Then, C V 1 = σ 1 x - 1 × 100 ⇒ x - 1 = 18 × 100 60 = 30 C V 2 = σ 2 x - 2 × 100 ⇒ x - 2 = 15 × 100 75 = 20 Hence, x - 1 = 30 and x - 2 = 20