Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 10th

# 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 - Mathematics

Sum

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?

#### Solution

(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

Concept: Coefficient of Variation
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