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)	34	31	33
	43	23	29
	23	24	38
	37	28	43
	42	28	31
	34		36

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.)

Answer 1

Solution: We can use the excel ANOVA data analysis tool to find the test statistic and the critical value. The excel output is given below:

(a) Find the test statistic.

Answer: The test statistic is $\dpi{100} \boldsymbol{F=4.07}$

(b) Find the critical value.

Answer: The critical value is $\dpi{100} \boldsymbol{F_{critical}=6.51}$