Question

Only t exam. The exam and all StT 12-In a poll conducted, a random sample of adult Americans were asked. "How importance is a candidate looks when deciding to vote?" The results of the survey by political affiliation are shown in the table below. Do the sample data suggest that the proportion of adults who feel that a candidates looks is important differ based on political affiliation? Use a 0.05level of significance Democrat 220 329 Independent 156 260 Republican 270 351 Important Not important

Answer 1

Null hypothesis:Ho: proportion of adults who feels that a candidate looks is important is independent on political affiliation

Alternate hypothesis:Ha: proportion of adults who feels that a candidate looks is important is dependent on political affiliation

degree of freedom(df) =(rows-1)*(columns-1)=

2

for 2 df and 0.05 level of signifcance critical region       χ2=

5.991

Applying chi square test of independence:

Expected	Ei=row total*column total/grand total	Democrat	Independent	Republican	Total
	Important	223.62	169.44	252.94	646
	Not important	325.38	246.56	368.06	940
	total	549	416	621	1586
chi square    χ2	=(Oi-Ei)2/Ei	Democrat	Independent	Republican	Total
	Important	0.058	1.066	1.150	2.275
	Not important	0.040	0.733	0.791	1.564
	total	0.099	1.799	1.941	3.8389

as test statistic 3.839 does not fall in rejection region; we fail to reject null hypothesis

we do not have evidence at 0.05 level to conclude that proportion of adults who feels that a candidate looks is important is dependent on political affiliation