Reading proficiency:An educator wants to construct a

90

%

confidence interval for the proportion of elementary school children in Colorado who are proficient in reading.Part:0 / 3

0 of 3 Parts Complete

Part 1 of 3

(a) The results of a recent statewide test suggested that the proportion is

0.61

. Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of0.04

?

A sample of

elementary school children is needed to obtain a90

%

confidence interval with a margin of error of0.04

.