8.3 #47,50,52

Be sure to be as detailed and in-depth as possible with the answers. Thanks.

47. The article "Racial Stereotypes in Children's Television Commercials" (J. of Adver. Res., 2008: 80-93) reported the following frequencies with which ethnic characters appeared in recorded commercials that aired on Philadelphia television stations. Ethnicity: African American Asian Caucasian Hispanic Frequency: 57 11 330 6 The 2000 census proportions for these four ethnic groups are .177, .032, .734, and .057, respectively. Does the data suggest that the proportions in commercials are different from the census proportions? Carry out a test of appropriate hypotheses using a significance level of .01.

50. A random sample of smokers was obtained, and each individual was classified by both gender and age when he or she first started smoking. The data in the accompanying table is consistent with summary results reported in the article "Cigarette Tar Yields in Relation to Mortality in the Cancer Prevention Study II Prospective Cohort" (British Med. J., 2004: 72-79). Gender Male Female ,16 25 10 Age 16-17 24 32 18-20 28 17 .20 19 34

a. Calculate the proportion of males in each age category; do the same for females. Based on these proportions, does it appear there might be an association between gender and the age when an individual first smokes?

b. Carry out a test of hypotheses to decide whether there is an association between the two factors.

52. A random sample of individuals who drive to work in a large metropolitan area was obtained, and each individual was categorized with respect to both size of vehicle and commuting distance (in miles). Does the accompanying data suggest that there is an association between type of vehicle and commuting distance? Commuting Distance 0 2 ,10 10 2 ,20 $20 Type of vehicle Subcompact 6 27 19 Compact 8 36 17 Midsize 21 45 33 Full-size 14 18 6 X 2 5 14.16

a. Does this situation call for a test of homogeneity or a test of independence?

b. State and test the appropriate hypotheses using 5 .05.