Joan’s Nursery specializes in custom-designed landscaping for residential areas. The estimated labor cost associated with a particular landscaping proposal is based on the number of plantings of trees, shrubs, and so on to be used for the project. For cost- estimating purposes, managers use two hours of labor time for the planting of a medium-sized tree. Actual times from a sample of 10 plantings during the past month follow (times in hours).

1.7 1.5 2.6 2.2 2.4 2.3 2.6 3.0 1.4 2.3

With a .05 level of significance, test to see whether the mean tree-planting time differs from two hours.

a. State the null and alternative hypotheses.

b. Compute the sample mean.

c. Compute the sample standard deviation.

d. What is the p-value?

e. What is your conclusion?