Question

The mean and standard deviation of marks obtained by 40 students of a class in three subjects Mathematics, Science and Social Science are given below

Subject	Mean	SD
Mathematics	56	12
Science	65	14
Social Science	60	10

Which of the three subjects shows more consistent and which shows less consistent in marks?

Answer 1

(i) Mathematics:

Mean `(barx)` = 56

Standard deviation (σ) = 12

Coefficient variation (CV₁) = `sigma/(barx) xx 100`

= `12/56 xx 100`

= `1200/56`

= 21.43

(ii) Science:

Mean `(barx)` = 65, Standard deviation (σ) = 14

Coefficient variation (CV₂) = `14/65 xx 100`

= `1400/65`

= 21.54

(iii) Social:

Mean `(barx)` = 60, Standard devaition (σ) = 10

Coefficient variation (CV₃) = `10/60 xx 100`

= `1000/60`

= 16.67

Science shows the more consistent

Social science shows the less consistent