The sum and the sum of squares of length x (in cm) and weight y (in g) of 50 plant products are given below:
∑50i=1xi=212, ∑50i=1x2i=902.8, ∑50i=1yi=261 and ∑50i=1y2i=1457.6
Which is more variable, the length or weight?
var (x)=150.∑50i=1 x2i−(150.∑50i=1xi)2=(902.850)−(21250)2=451.425−(10625)2
=(451.425−11236625)=(11285−11236625)
=49625=0.078
var (y)=150.∑50i=1y2i−(150.∑50i=1yi)2={1457.650−(26150)2}
={29.152−(5.22)2}=29.152−27.2484
= 1.9036
∴ var(x) < var (y)