Digital media education in advertising. The use of digital media (e.g., Facebook, Twitter, e-Readers, mobile phone apps) in advertising has exploded in the past several years. An article in the Journal of Advertising Education, November 2019) examined how advertising and public relations programs in the United States have incorporated digital media in their university courses. Data were collected on 4,780 advertising major courses. First, each course was categorized according to course type (elective, required in a group, or core required); then, the researchers determined whether each course incorporated digital media or not. The data (number of courses in each category) are summarized in the following table. Elective Required in a Group Core Required TOTAL Digital Media 321 346 461 1128 Non-digital 921 1023 1708 3652 TOTAL 1262 1368 2169 4780 Source: Fang, F., Wei, W., and Huang, H. “Keeping Up With Fast-Paced Industry Changes—Digital Media Education in U.S. Advertising and PR Programs”, Journal of Advertising Education, Volume 13, Number 2, November 2019 (Table 1).

a. Identify the two qualitative variables measured for each advertising course.

b. Give the null and alternative hypothesis for testing whether or not a course incorporates digital media depends on course type.

c. Find the expected number of courses in each cell of the contingency table, assuming that the null hypothesis is true.

d. Compute the x2 test statistic and compare your answer with the test statistic shown on the accompanying XLSTAT printout (below).

e. Find the rejection region for the test using a = .05 and compare your answer to the critical value shown on the accompanying XLSTAT printout.

f. Make the appropriate conclusion using both the rejection region method and the p-value (shown on the XLSTAT printout). g. Find a 95% confidence interval for the difference between the proportions of elective and core courses that incorporate digital media. (See Section 10.3.) Interpret the result practically