Question

If X12 = 10000 xi
10000 xi = 400 and C V = 50% then value of n is​

Answer 1

Answer:

If xi2 = 10000, xi = 400 and C.V = 50% then value of n is _______  (a) 5 (b) 40  (c) 20 (d) 25

Step-by-step explanation:

The correct option (c) 20  

xi2 = 10000

xi = 400 

C.V = 50%

Now x = [(∑xi)/n] = (400/n)

and S = √[{(∑xi2)/n} – (x)2]

∴ S = √[{(10000)/n} – (400/n)2]

∴ S = [√(10000n – 160000)/n] ......(1)

also (S/x) = (50/100) = (1/2)

∴ [S/(400/n)] = (1/2) ⇒ (Sn/400) = (1/2) ......(2)

∴ (200)2 = 10000n – 160000 ------- from (1) & (2)

∴ n = 20.