Question

A random sample of companies in electric utilities (I), financial services (II), and food processing (III) gave the following information regarding annual profits per employee (units in thousands of dollars).

I	II	III
49.4	55.8	38.8
43.2	24.7	37.4
32.1	41.4	10.7
27.2	29.6	32.5
38.3	39.7	15.7
36.3		42.1
20.6

Shall we reject or not reject the claim that there is no difference in population mean annual profits per employee in each of the three types of companies? Use a 5% level of significance.

(a) What is the level of significance?

State the null and alternate hypotheses.

H_o: ?₁ = ?₂ = ?₃; H₁: Not all the means are equal.   H_o: ?₁ = ?₂ = ?₃; H₁: Exactly two means are equal.    H_o: ?₁ = ?₂ = ?₃; H₁: All three means are different .H_o: ?₁ = ?₂ = ?₃; H₁: At least two means are equal.

(b) Find SS_TOT, SS_BET, and SS_W and check that SS_TOT = SS_BET + SS_W. (Use 3 decimal places.)

SSTOT	=
SSBET	=
SSW	=

Find d.f._BET, d.f._W, MS_BET, and MS_W. (Use 3 decimal places for MS_BET, and MS_W.)

dfBET	=
dfW	=
MSBET	=
MSW	=

Find the value of the sample F statistic. (Use 3 decimal places.)


What are the degrees of freedom?
(numerator)
(denominator)

(c) Find the P-value of the sample test statistic. (Use 4 decimal places.)

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis?

Since the P value is greater than the level of significance at ? = 0.05, we do not reject H₀.Since the P value is less than or equal to the level of significance at ? = 0.05, we reject H₀.    Since the P value is greater than the level of significance at ? = 0.05, we reject H₀.Since the P value is less than or equal to the level of significance at ? = 0.05, we do not reject H₀.

(e) Interpret your conclusion in the context of the application.
At the 5% level of significance there is insufficient evidence to conclude that the means are not all equal.At the 5% level of significance there is sufficient evidence to conclude that the means are all equal.    At the 5% level of significance there is insufficient evidence to conclude that the means are all equal.At the 5% level of significance there is sufficient evidence to conclude that the means are not all equal.

Answer 1

a)

level of significance =0.05

Ho: 1 = 2 = 3; H1: Not all the means are equal.

b)

SSTOT=2222.889

SSBET =220.744

SSW =2002.145

dfBET =2

dfW=15

MSBET=110.372

MSW =133.476

value of the sample F statistic =0.827

numerator df =2

denominator df =15

c)P-value =0.4563 ( [please try 0.4564 if this comes wrong)

d)

Since the P value is greater than the level of significance at ? = 0.05, we do not reject H0

e)

At the 5% level of significance there is insufficient evidence to conclude that the means are not all equal