How do Americans feel about online discounts tailored to their individual interests? A survey of 1,000 adult Internet users found that 37% of the 18 to 24 year olds, 44% of 25 to 34 year olds, 50% of 35 to 49 year olds, 58% of 50 to 64 year olds, and 70% of 65 to 89 year olds opposed such discounts. (Data extracted from S. Clifford, "Tracked for Ads? Many Americans Say No Thanks," The New York Times, September 30, 2009, p. B3.) Suppose that the survey was based on 200 respondents in each of five age groups: 18 to 24, 25 to 34, 35 to 49, 50 to 64, and 65 to 89.
a. At the 0.05 level of significance, is there evidence of a difference among the age groups in the opposition to discounts on web pages tailored to their interests?
b. Compute the p-value and interpret its meaning.
c. If appropriate, use the Marascuilo procedure and to determine which age groups are different.