Question

A music industry researcher wants to estimate, with a 95% confidence level, the proportion of young urban people (ages 21 to 35 years) who go to at least 3 concerts a year. Previous studies show that 42% of those people (21 to 35 year olds) interviewed go to at least 3 concerts a year. The researcher wants to be accurate within 1% of the true proportion. Find the minimum sample size necessary.

Choose one:

a) 9604

b) 9385

c) 9358

d) 9220

Answer 1

The correct option is (c), i.e., 9358.

The formula for calculating the minimum required sample size for a confidence interval estimate of the population parameter p is given by

where,

the prior estimate of p is given as , i.e., 42%

Margin of error, E=0.01, i.e., within 1% of the true proportion.

For 95% confidence ,

So the minimum sample size required is