Do workers prefer to buy lunch rather than pack their own lunch? A survey of employed Americans found that 75% of the 18- to 24-year-olds, 77% of the 25- to 34-year-olds, 72% of the 35- to 44-year-olds, 58% of the 45- to 54-year-olds, 57% of the 54- to 64-year-olds, and 55% of the 65 +-year-olds buy lunch throughout the work week. (Data extracted from bit.ly/z99CeN.) Suppose the survey was based on 200 employed Americans in each of six age groups: 18 to 24, 25 to 34, 35 to 44, 45 to 54, 55 to 64, and 65+.
a. At the 0.05 level of significance, is there evidence of a difference among the age groups in the preference for lunch?
b. Determine the p-value in (a) and interpret its meaning.
c. If appropriate, use the Marascuilo procedure and a = 0.05 to determine which age groups differ.