Question

Alba 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 planting of trees, shrubs, and so on to be used for the project. For cost estimating purposes, managers use at most 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 (time in hours): 1.7   1.5 2.6 2.2 2.4 2.3 2.6 3 1.4 2.3

Is there sufficient evidence that the mean tree planting time is more than two hours for planting a medium-sized tree? What is your conclusion?

:  

:  

P-Value:

Conclusion:

Please provide the answer for Ho, H1, P-value, and conclusion.

Answer 1

Solution:

x	x2
1.7	2.89
1.5	2.25
2.6	6.76
2.2	4.84
2.4	5.76
2.3	5.29
2.6	6.76
3	9
1.4	1.96
2.3	5.29
∑x=22	∑x2=50.8

Mean ˉx=∑xn

=1.7+1.5+2.6+2.2+2.4+2.3+2.6+3+1.4+2.3/10

=22/10

=2.2

Sample Standard deviation S=√∑x2-(∑x)2nn-1

=√50.8-(22)210/9

=√50.8-48.4/9

=√2.4/9

=√0.2667

=0.5164

This is the right tailed test .

The null and alternative hypothesis is ,

H0 :   < 2

2Ha : > 2

Test statistic = t

= ( - ) / S / n

= (2.2 -2) / 0.52 / 10

= 1.240

Test statistic = t =  1.240

P-value =0.1232