Question

Researchers interested in the effect of movies on adolescent smoking watched movies released between 2000 and 2005, paying attention to characters who were depicted smoking in the movie.

These characters were classified as “good guys,” “bad guys,” or “neutral.” They also noted the gender of each smoker. They were interested in whether there is an association between gender and character type for movie characters who smoke.

Here is the data:

	Good Guy	Bad Guy	Neutral	Total
Male	255	106	130	491
Female	85	12	49	146
Total	340	118	179	637

(a) For the chi square test of independence, what is the EXPECTED number for female good guys? Give your answer to 1 decimal place.____

(b) The chi square test statistic is X² = _______________________                     

(c) The p-value is 0.001. State the conclusion, for αλπηα = 0.01. Your answer should refer to the context, not just “reject” or “do not reject.”____________________

Answer 1

a) EXPECTED number for female good guys =row total*column total/grand total =146*340/637 =77.9

b)

applying chi square test:

Ei=row total*column total/grand total	good guy	bad guy	neutral	Total
male	262.07	90.95	137.97	491
female	77.93	27.05	41.03	146
total	340	118	179	637
=(Oi-Ei)2/Ei	good guy	bad guy	neutral	Total
male	0.1908	2.4888	0.4608	3.140
female	0.6418	8.3699	1.5496	10.561
total	0.833	10.859	2.010	13.702

chi square test statistic X²=13.702

c) reject Ho ; we have sufficient evidence to conclude that there is an association between gender and character type for movie characters who smoke