Exercise 11-39 Lester Hollar is vice president for human resources for a large m
ID: 3315614 • Letter: E
Question
Exercise 11-39
Lester Hollar is vice president for human resources for a large manufacturing company. In recent years, he has noticed an increase in absenteeism that he thinks is related to the general health of the employees. Four years ago, in an attempt to improve the situation, he began a fitness program in which employees exercise during their lunch hour. To evaluate the program, he selected a random sample of eight participants and found the number of days each was absent in the six months before the exercise program began and in the last six months. Below are the results.
At the 0.01 significance level, can he conclude that the number of absences has declined? Hint: For the calculations, assume the "Before" data as the first sample.
Lester Hollar is vice president for human resources for a large manufacturing company. In recent years, he has noticed an increase in absenteeism that he thinks is related to the general health of the employees. Four years ago, in an attempt to improve the situation, he began a fitness program in which employees exercise during their lunch hour. To evaluate the program, he selected a random sample of eight participants and found the number of days each was absent in the six months before the exercise program began and in the last six months. Below are the results.
Explanation / Answer
> data1=read.csv(file.choose(),header=T)
> data1
Employee Before After
1 1 7 4
2 2 6 4
3 3 7 3
4 4 5 2
5 5 4 2
6 6 5 6
7 7 6 3
8 8 5 7
> attach(data1)
#Critical value
> qt(0.01,7,lower.tail=F)
[1] 2.997952
Reject H0 if t > 2.998.
> t.test(Before,After,paired=F,alt="g",conf.level=0.99)
Welch Two Sample t-test
data: Before and After
t = 2.3616, df = 11.309, p-value = 0.01856
alternative hypothesis: true difference in means is greater than 0
99 percent confidence interval:
-0.2550628 Inf
sample estimates:
mean of x mean of y
5.625 3.875
Test statistic : t = 2.362
p-value = 0.01856, i.e between 0.005 and 0.05
Decision : Do not Reject H0.
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