The branch manager of a pet supply store wants to study characteristics of customers of his store. In particular, he decides to focus on two variables: the amount of money spent by customers and whether the customers own only one cat.

1. If he wants to have 95% confidence of estimating the true population mean amount spent in his store within ± $1.50 and the standard deviation is assumed to be $10, what sample size is needed with calculations?

2. If he wants to have 90% confidence of estimating the population proportion of customers who own only a cat to within ± 0.045, what sample size is needed with calculations?

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1. If he wants to have 95% confidence of estimating the true population mean amount spent in his store within ± $1.50 and the standard deviation is assumed to be $10, what sample size is needed with calculations?

Solution. Assume that the standard ...

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The solution consists of details of how to find out the minimum sample size.

... 0.3)^2 That is, n > 1536.9401 Thus the minimum sample size required is ... Result Sample Size Needed 1537. ... The expert finds the sample amount for population means. ...

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