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Random samples of employees from three different departments of MNM Corporation

ID: 2906631 • Letter: R

Question

Random samples of employees from three different departments of MNM Corporation showed the following yearly incomes (in $1,000).

Department A

Department B

Department C

40

46

46

37

41

40

43

43

41

41

33

48

35

41

39

38

42

44

     Anova: Single factor

SUMMARY

Groups

Count

Sum

Average

Variance

Department A

6

234

39

8.4

Department B

6

246

41

18.8

Department C

6

258

43

12.8

ANOVA

Source of Variation

SS

df

MS

F

P-value

F crit

Between Groups

48

2

24

1.8

0.20

3.68

Within Groups

200

15

13.33

Total

248

17

a.State the null and alternative hypotheses.

b.What is the test statistic from the ANOVA table?

c.With ? = 0.05, what is the critical value?

d.At ? = .05, test to determine if there is a significant difference among the average incomes of the employees from the three departments. Use the critical value approach. Write out the decision rule.

Department A

Department B

Department C

40

46

46

37

41

40

43

43

41

41

33

48

35

41

39

38

42

44

Explanation / Answer

a)null hypothesis:Ho: average incomes of the employees from the three departments are equal.

alternate hypotheiss: Ha: not all  three departments have equal average incomes of the employees

b)

test statistic from ANOVA table F =1.8

c)

critical value F=3.68

d)

deicision rule:reject Ho if test statistic F >3.68

as test statistic is not in critical region we can nnot reject null hypothesis

we do not have suffcient evidence to conclude that there is a significant difference among the average incomes of the employees from the three departments.