# The following table gives weights of the students of class A. Calculate the Coefficient of variation. (Given:0.8=0.8944) Weight (in kg) Class A 25 – 35 8 35 – 45 4 45 – 55 8 - Mathematics and Statistics

Sum

The following table gives weights of the students of class A. Calculate the Coefficient of variation. ("Given": sqrt0.8 = 0.8944)

 Weight (in kg) Class A 25 – 35 8 35 – 45 4 45 – 55 8

#### Solution

 Weight (in kg) Class A(fi) Mid value(xi) fixi fixi2 25 – 35 8 30 240 7200 35 – 45 4 40 160 6400 45 – 55 8 50 400 20000 Total N = 20 ∑fixi = 800 ∑fixi2 = 33600

bar"x" = (sum"f"_"i""x"_"i")/"N"

= (800)/(20)
= 40

Var(X) = sigma_"x"^2=(sum"f"_"i""x"_"i"^2)/"N"-(bar"x")^2

= 33600/20-(40)^2

= 1680 − 1600
= 80
∴ S.D. = σx = sqrt80

= sqrt((100xx8)/10)

= 10sqrt0.8

= 10(0.8944)
= 8.944

C.V. (X) = sigma_"x"/bar"x" xx 100

= (8.944)/(40) xx 100

= 22.36%

Concept: Coefficient of Variation
Is there an error in this question or solution?