How's the economy? A pollster wants to construct a 95 % confidence interval for the proportion of adults who believe that economic conditions are getting better.
(a) A poll taken in July 2010 estimates this proportion to be 0.41 . Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.02 ?
(b) Estimate the sample size needed if no estimate of p is available. Part 1 of 2
(a) A poll taken in July 2010 estimates this proportion to be 0.41 . 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 a 95 % confidence interval with a margin of error of 0.02 . Part 2 of 2
(b) Estimate the sample size needed if no estimate of p is
available.
A sample of adults is needed to obtain a 95 % confidence interval
with a margin of error of 0.02
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