Question

The mean and standard deviation of marks obtained by 50 students of a class in three subjects, Mathematics, Physics and Chemistry are given below: Subject Mathematics Physics Chemistry Mean 42 32 40.9 Standard deviation 12 15 20 Which of the three subjects shows the highest variability in marks and which shows the lowest?

Answer 1

Standard deviation of Mathematics, Physics and Chemistry are 12, 15 and 20 respectively.

Mean of Mathematics, Physics and Chemistry are 42, 32 and 40.9 respectively.

Coefficient of variance of Mathematics,

Mathematics ( C.V. )= 12 42 ×100 =28.57

Coefficient of variance of Physics,

Physics ( C.V. )= 15 32 ×100 =46.87

Coefficient of variance of Chemistry,

Chemistry ( C.V. )= 20 40.9 ×100 =48.89

Since subject with greater C.V. is more variable than others. Thus, the highest variability in marks is in Chemistry and the lowest variability in the marks is in Mathematics.