In each of the following situations, indicate the statistical analysis you would conduct and the appropriate test or test statistic that should be used.
a. Consumer preferences for Dove soap were obtained on an 11-point Likert scale. The same consumers were then shown a commercial about Dove. After the commercial, preferences for Dove were again measured. Has the commercial been successful in inducing a change in preferences?
b. Respondents in a survey of 1,000 households were asked to indicate their frequency of domestic air travel on an interval scale. They were also classified “as being in high-, medium-, or low-income categories. Is the frequency of domestic air travel related to income level?
c. In a telephone survey using a representative sample of 3,000 households, the respondents were asked to indicate their preference for fast-food restaurants using a 7-point Likert-type scale. The sample was divided into small and large households based on a median split of the household size. Does preference for fast-food restaurants vary by household size?