Question

NASA is conducting an experiment to find out the fraction of people who black out at G forces greater than 6. In an earlier study, the population proportion was estimated to be 0.39

How large a sample would be required in order to estimate the fraction of people who black out at 66 or more Gs at the 80% confidence level with an error of at most 0.03? Round your answer up to the next integer.

Answer 1

Given that, estimate of population proportion (p) = 0.39

margin of error (E) = 0.03

A 80% confidence level has significance level of 0.20 and critical value is,

We want to find, the sample size (n),

Therefore, required sample size is 434.

Note : if we used critical value = 1.28155 (rounded to 5 decimal places) then required sample size will be, n = 435