# Question: A sample of 20 pages was taken from a Yellow

A sample of 20 pages was taken from a Yellow Pages directory. On each page, the mean area devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text). The data (in square millimeters) are shown below:

(a) Construct a 95 percent confidence interval for the true mean.

(b) What sample size would be needed to obtain an error of ±20 square millimeters with 95 percent confidence? (Data DisplayAds are based on a project by MBA student Daniel R. Dalach.)

(a) Construct a 95 percent confidence interval for the true mean.

(b) What sample size would be needed to obtain an error of ±20 square millimeters with 95 percent confidence? (Data DisplayAds are based on a project by MBA student Daniel R. Dalach.)

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