Question

An employment agency wants to see which of three types of ads in the help-wanted section of local newspapers is the most effective. Three types of ads (big headlines, straightforward, and bold print) were randomly alternated over a period of weeks, and the number of people responding to the ads was noted each week.

	Type of Advertisement
	Big Headline	Straightforward	Bold Print
Number of responses (replicates)	26	24	33
	30	24	28
	45	31	34
	35	25	42
	40	22	34
	43		32

Do these data support the null hypothesis that there is no difference in the effectiveness of the ads, as measured by the mean number responding, at the .01 level of significance?

(a) Find the test statistic. (Give your answer correct to two decimal places.)


(b) Find the critical value. (Give your answer correct to two decimal places.)

(c) State the appropriate conclusion.

Reject the null hypothesis, there is not significant evidence of a difference in effectiveness of the ads. Reject the null hypothesis, there is significant evidence of a difference in effectiveness of the ads.     Fail to reject the null hypothesis, there is significant evidence of a difference in effectiveness of the ads. Fail to reject the null hypothesis, there is not significant evidence of a difference in effectiveness of the ads.

You may need to use the appropriate table in Appendix B to answer this question.

Answer 1

applying one way ANOVA on above data:

Source of Variation	SS	df	MS	F		F crit
Between Groups	371.93	2.00	185.96	6.01		6.51
Within Groups	433.13	14.00	30.94
Total	805.06	16.00

a)

test statistic =6.01

b)

critical value =6.51

c) Fail to reject the null hypothesis, there is not significant evidence of a difference in effectiveness of the ads.