Hays Medical Center wants to estimate the percentage of adults who exercise at least 1 hour per week. How large a sample should be selected in order to estimate this proportion with a 90% confidence level and a margin of error of at most 5%? (Assume no preliminary estimate of p-hat is available.)
When there is no preliminary estimate, consider = 0.5
Margin of error, E = Z*
For 90% confidence interval, Z* = 1.645
E = 5% = 0.05
Therefore, 0.05 = 1.645 x
= 16.45
n = 271 (rounded up)
Sample size to be selected = 271
Hays Medical Center wants to estimate the percentage of adults who exercise at least 1 hour...
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