Question

A public health researcher wishes to estimate the proportion of adults in the U.S. that have high blood pressure. Obtain a sample size that will ensure a margin of error of at most 0.006 for a 92% confidence interval.

Answer 1

Solution :

Given that,

= 0.5

1 - = 0.5

margin of error = E =0.006

At 92% confidence level the z is ,

Z/2 =1.751( Using z table )

Sample size = n = (Z/2 / E)2 * * (1 - )

= (1.751 / 0.006)2 * 0.5* 0.5

= 21291.6

Sample size =21292