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# Testing of hypothesis and estimating p-values

Chapter 11

24.The liquid chlorine added to swimming pools to combat algae has a relatively short shelf life before it loses its effectiveness. Records indicate that the mean shelf life of a 5-gallon jug of chlorine is 2,160 hours (90 days). As an experiment, Holdlonger was added to the chlorine to find whether it would increase the shelf life. A sample of nine jugs of chlorine had these shelf lives (in hours):

2,159 2,170 2,180 2,179 2,160 2,167 2,171 2,181 2,185

At the .025 level, has Holdlonger increased the shelf life of the chlorine? Estimate the pvalue.

Chapter 11

18

The Tampa Bay (Florida) Area Chamber of Commerce wanted to know whether the mean weekly salary of nurses was larger than that of school teachers. To investigate, they collected the following information on the amounts earned last week by a sample of school teachers and nurses.
School teachers (\$) 845 826 827 875 784 809 802 820 829 830 842 832

Nurses (\$) 841 890 821 771 850 859 825 829

Is it reasonable to conclude that the mean weekly salary of nurses is higher? Use the .01
significance level. What is the p-value?

Chapter 12

12.

Given the following sample information, test the hypothesis that the treatment means are
equal at the .05 significance level.
Treatment 1 Treatment 2 Treatment 3
3 9 6
2 6 3
5 5 5
1 6 5
3 8 5
1 5 4
4 1
7 5
6
4
a. State the null hypothesis and the alternate hypothesis.
b. What is the decision rule?
c. Compute SST, SSE, and SS total.
d. Complete an ANOVA table.
e. State your decision regarding the null hypothesis.
f. If H0 is rejected, can we conclude that treatment 2 and treatment 3 differ? Use the
95 percent level of confidence.

#### Solution Summary

Test if there is difference in means

\$2.19