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).

2.8 1.3 2.5 2.3 1.4 1.7 2.5 3.3 2.7 2.6

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.

H0: ______ 2

Ha: ______ 2

b. Compute the sample mean.

_____ (to 2 decimals)

c. Compute the sample standard deviation.

_____ (to 4 decimals)

d. Find the test statistic and p-value.

t _______ (to 3 decimals)

p-value _______

e. What is your conclusion?

We ______ reject the null hypothesis. There ______ enough evidence to prove that the mean tree-planting time differs from 2 hours.