Question

Chapter 6, Section 1-D, Exercise 008 Impact of Sample Size on Accuracy Compute the standard error for sample proportions from a population with proportion p = 0.55 for sample sizes n=40. n=150 and n=1200. Round your answers to three decimal places.

Sample size            SE

n=40    _________

n=150                _________

n=120    _________

Answer 1

Solution

Given that,

p = 0.55

1 - p = 1 - 0.55 = 0.45

a) n = 40

=  [p ( 1 - p ) / n] =   [(0.55 * 0.45) / 40] = 0.079

b) n = 150

=  [p ( 1 - p ) / n] =   [(0.55 * 0.45) / 150] = 0.041

c) n = 1200

=  [p ( 1 - p ) / n] =   [(0.55 * 0.45) / 1200] = 0.014