Question

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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).

1.6

1.6

2.5

2.3

2.4

2.3

2.6

3.0

1.4

2.3

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

(a) State the null and alternative hypotheses.

a) H₀: μ = 2

b) H_a: μ ≠ 2

a) H₀: μ > 2

b) H_a: μ ≤ 2

    

a) H₀: μ ≤ 2

b) H_a: μ > 2

a) H₀: μ < 2

b) H_a: μ ≥ 2

a) H₀: μ ≥ 2

b) H_a: μ < 2

(b) Compute the sample mean.

?

(c) Compute the sample standard deviation. (Round your answer to three decimal places.)

?

(d) What is the test statistic? (Round your answer to three decimal places.)

?

What is the p-value? (Round your answer to four decimal places.)

p-value = ?

(e) What is your conclusion?

a) Do not reject H₀. We can conclude that the mean tree-planting time differs from two hours. There is a reason to change from the two hours for cost estimating purposes.

b) Reject H₀. We cannot conclude that the mean tree-planting time differs from two hours. There is no reason to change from the two hours for cost estimating purposes.    

c) Reject H₀. We can conclude that the mean tree-planting time differs from two hours. There is a reason to change from the two hours for cost estimating purposes.

d) Do not reject H₀. We cannot conclude that the mean tree-planting time differs from two hours. There is no reason to change from the two hours for cost estimating purposes.

Answer 1