After scanning the UPC code of a 4 GB flash memory card using his smartphone, Michael Sullivan received the following prices for the goods at a variety of online retailers. Treat these data as a simple random sample of all online retailers.

(a) Determine a point estimate for the population mean price of the memory card.

(b) Use the normal probability plot and boxplot shown next to assist in verifying the requirements for constructing a confidence interval for the mean price.

(c) Construct and interpret a 95% confidence interval to estimate the mean price of a 4 GB flash memory card.

(d) Construct and interpret a 99% confidence interval to estimate the mean price of a 4 GB flash memory card.

(e) What happens to the interval as the level of confidence is increased? Explain why this is a logical result.

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13.49 13.76 14.99 14.75 12.25 15.95 17.88 20.49 14.99 15.27 Probability Plot of Price Normal a 15 25 Price Percent