Question

The Advisory Committee on Immunization Practices (ACIP) recommends Flu shots for anyone older than 6 months. A recent survey found that 37% of US adults were administered the Flu shot. If the committee wants to estimate the proportion of all US adults who will receive the Flu shot this year, how many Adults must be sampled to estimate the proportion within 3 percentage points using a 95% confidence level?

Answer 1

Solution,

Given that,

= 0.37

1 - = 1 - 0.37 = 0.63

margin of error = E = 0.03

At 95% confidence level

= 1 - 95%

= 1 - 0.95 =0.05

/2 = 0.025

Z/2 = Z0.025  = 1.96

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

= (1.96 / 0.03)2 * 0.37 * 0.63

= 994.97

sample size = n = 995