A department store manager wants to estimate the mean amount spent by all customers at this store at a 95% confidence level. The manager knows that the population standard deviation of amounts spent by all customers at this store is $35 . What minimum sample size should he choose so that the estimate is within $3 of the population mean μ?
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The z-score for a 95% confidence level is approximately 1.96. Show more…
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A department store manager wants to estimate the mean amount spent by all customers at this store at a $98 \%$ confidence level. The manager knows that the standard deviation of amounts spent by all customers at this store is $\$ 31$. What minimum sample size should he choose so that the estimate is within $\$ 3$ of the population mean?
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Ana Carolina D.
$$ \begin{array}{l}{\text { Christmas Presents How large a sample is needed to }} \\ {\text { estimate the population mean for the amount of money a }} \\ {\text { person spends on Christmas presents within } \$ 2 \text { and be } 95 \%} \\ {\text { confident? The standard deviation of the population }} \\ {\text { is } \$ 7.50 .}\end{array} $$
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