More shoppers do their majority of grocery shopping on Saturday than any other day of the week

More shoppers do their majority of grocery shopping on Saturday than any other day of the week. However, is the day of the week a person does the majority of grocery shopping dependent on age? A study cross-classified grocery shoppers by age and major shopping day ("Major Shopping by Day ," Progressive Grocer Annual Report, April 30, 2002). The data were reported as percentages and no sample sizes were given.

AGE
Major Shopping Day Under 35 35-54 Over 54
Saturday 24% 28% 12%
A day other than Saturday 76% 72% 88%
Source: Extracted from "Major Shopping Day," Progressive Grocer Annual Report, April 30, 2002.

Assume that 200 shoppers for each age category were surveyed.

a. Is there evidence of a significant difference among the age groups with respect to major grocery shopping day? (Use p = 0.05.)
b. Determine the p-value in (a) and interpret its meaning.