A New York Times article reported that a survey conducted in 2014 included 36,000 adults, with 3.72% of them being regular users of e-cigarettes. Because e-cigarette use is relatively new, there is a need to obtain today's usage rate. How many adults must be surveyed now if a confidence level of 90% and a margin of error of 2.5 percentage points are wanted? Complete parts (a) through (c) below.
a. Assume that nothing is known about the rate of e-cigarette usage among adults.
n =
(Round up to the nearest integer.)
b. Use the results from the 2014 survey.
n =
(Round up to the nearest integer.)
c. Does the use of the result from the 2014 survey have much of an effect on the sample size?
A. No, using the result from the 2014 survey only slightly reduces the sample size.
B. Yes, using the result from the 2014 survey only slightly increases the sample size.
C. No, using the result from the 2014 survey does not change the sample size.
D. Yes, using the result from the 2014 survey dramatically reduces the sample size.
