Question

# A random sample of companies in electric utilities (I), financial services (II), and food processing (III)...

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 49.7 55.8 38.9 43.3 25.3 37.7 32.9 41.7 10.7 27.4 29.2 32.6 38.3 39.6 15.2 36.8 42.5 20.1

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 1% level of significance.

(a) What is the level of significance?

State the null and alternate hypotheses.

Ho: μ1 = μ2 = μ3; H1: Exactly two means are equal.Ho: μ1 = μ2 = μ3; H1: Not all the means are equal.    Ho: μ1 = μ2 = μ3; H1: All three means are different.Ho: μ1 = μ2 = μ3; H1: At least two means are equal.

(b) Find SSTOT, SSBET, and SSW and check that SSTOT = SSBET + SSW. (Use 3 decimal places.)

 SSTOT = SSBET = SSW =

Find d.f.BET, d.f.W, MSBET, and MSW. (Use 3 decimal places for MSBET, and MSW.)

 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.

P-value > 0.1000.050 < P-value < 0.100    0.025 < P-value < 0.0500.010 < P-value < 0.0250.001 < P-value < 0.010P-value < 0.001

(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 α = 0.01, we do not reject H0.Since the P-value is less than or equal to the level of significance at α = 0.01, we reject H0.    Since the P-value is greater than the level of significance at α = 0.01, we reject H0.Since the P-value is less than or equal to the level of significance at α = 0.01, we do not reject H0.

(e) Interpret your conclusion in the context of the application.

At the 1% level of significance there is insufficient evidence to conclude that the means are not all equal.At the 1% level of significance there is sufficient evidence to conclude that the means are all equal.    At the 1% level of significance there is insufficient evidence to conclude that the means are all equal.At the 1% level of significance there is sufficient evidence to conclude that the means are not all equal.

(f) Make a summary table for your ANOVA test.

 Source of Variation Sum of Squares Degrees of Freedom MS F Ratio P Value Test Decision Between groups ---Select--- p-value > 0.100 0.050 < p-value < 0.100 0.025 < p-value < 0.050 0.010 < p-value < 0.025 0.001 < p-value < 0.010 p-value < 0.001 ---Select--- Do not reject H0. Reject H0. Within groups Total

d)

Since the P-value is less than or equal to the level of significance at alpha= 0.01, we reject H0.

e)

At the 1% level of significance there is sufficient evidence to conclude that the means are all equal.

f)