Question

Consider an x distribution with standard deviation σ = 40. (For each answer, enter an exact number.)

(a) If specifications for a research project require the standard error of the corresponding distribution to be 5, how large does the sample size need to be?

n=

(b) If specifications for a research project require the standard error of the corresponding distribution to be 1, how large does the sample size need to be?

n=

Answer 1

Solution :

Given that,

σ = 40

The sampling distribution of standard deviation is ,  

= / n

(a)

= 5

n = 6 / = 40 / 5 = 8

n = 64

(b)

= 1

n = 6 / = 40 / 1 = 40

n = 1600