How's the economy? A pollster wants to construct an

80

%

confidence interval for the proportion of adults who believe that economic conditions are getting better.

Part:0 / 2

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Part 1 of 2

(a) A poll taken in July

2010

estimates this proportion to be

0.24

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

0.02

?

A sample of adults is needed to obtain an 80 % confidence interval with a margin of error of 0.02 .