An average lawn has a mean of 21 blades of grass per square inch. A garden store sells an expensive fertilizer designed to transform an average lawn into a lush, thick carpet within three weeks. To...

An average lawn has a mean of 21 blades of grass per square inch. A garden store sells an expensive fertilizer designed to transform an average lawn into a lush, thick carpet within three weeks. To test the claim, a random sample of average lawn plots was obtained. Each was treated with the fertilizer according to the instructions on the package. Three weeks later the density of each plot was measured by counting the blades of grass per square inch. The summary statistics were n =32, x = 22.4. Is there any evidence to suggest the fertilizer improves the thickness of an average lawn? Assume s 5 2.7 and use a = 0.005.

Based on test results, Speedtest.net publishes an Internet download index for countries all over the world. In July 2013, the mean download speed for the entire world was 13.91 Mbps. A random sample of states was obtained and the download index for each was recorded. Assume the underlying population is normal and that
 . Is there any evidence to suggest that the download speed for the United States is greater than the world population mean? Use