Question

In what ways do advertisers in magazines use sexual imagery to appeal to youth? One study classified each of 1509 full-page or larger ads as "not sexual" or "sexual," according to the amount and style of the dress of the male or female model in the ad. The ads were also classified according to the target readership of the magazine. Here is the two-way table of counts.

	Magazine readership
Model dress	Women	Men	General interest	Total
Not sexual	351	527	256	1134
Sexual	209	85	81	375
Total	560	612	337	1509

(a) Summarize the data numerically and graphically. (Compute the conditional distribution of model dress for each audience. Round your answers to three decimal places.)

	Women	Men	General
Not sexual
Sexual

(b) Perform the significance test that compares the model dress for the three categories of magazine readership. Summarize the results of your test and give your conclusion. (Use α = 0.01. Round your value for χ² to two decimal places, and round your P-value to four decimal places.)

χ2 =
P-value =

Conclusion

Fail to reject the null hypothesis. There is significant evidence of an association between target audience and model dress.

Reject the null hypothesis. There is significant evidence of an association between target audience and model dress.    

Fail to reject the null hypothesis. There is not significant evidence of an association between target audience and model dress.

Reject the null hypothesis. There is not significant evidence of an association between target audience and model dress.

(c) All of the ads were taken from the March, July, and November issues of six magazines in one year. Discuss this fact from the viewpoint of the validity of the significance test and the interpretation of the results.

This is an SRS. This gives us reason to believe our conclusions might be suspect.

This is not an SRS. This gives us no reason to believe our conclusions are suspect.   

This is an SRS. This gives us no reason to believe our conclusions are suspect.

This is not an SRS. This gives us reason to believe our conclusions might be suspect.

Answer 1

a)dividing each value by column total:

	Women	Men	General interest
Not sexual	0.627	0.861	0.760
Sexual	0.373	0.139	0.240

b)

applying chi square test:

Ei=row total*column total/grand total	Women	Men	General interest	Total
Not sexual	420.83	459.91	253.25	1134
Sexual	139.17	152.09	83.75	375
total	560	612	337	1509
=(Oi-Ei)2/Ei	Women	Men	General interest	Total
Not sexual	11.5887	9.7861	0.0298	21.405
Sexual	35.0442	29.5930	0.0901	64.727
total	46.633	39.379	0.120	86.132

χ² = 86.132

p value =0.000

Reject the null hypothesis. There is significant evidence of an association between target audience and model dress.    

c)

This is not an SRS. This gives us reason to believe our conclusions might be suspec