Biology and Environment Science
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 σ = 2.7 and use a = 0.005.