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...

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  one and half 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).

2.3 0.9 2.1 1.4 3.2 2.4 2.1 1.8 3.3 1.4

With a 0.05 level of significance, test to see whether the mean tree-planting time differs from  one and half hours.

a. State the null and alternative hypotheses.

H0 : =u 1.5

Ha : not=u 1.5

b. Compute the sample mean.

  (to 1 decimal)

c. Compute the sample standard deviation.

  (to 3 decimals)

d.
What is the p-value?

e. What is your conclusion?

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