An Article in American Demographics investigated consumer habits at the mall. We tend to spend the most money when shopping on weekends, particularly on Sundays between 4:00 and 6:00 P.M. Wednesday-morning shoppers spend the least.15 Independent random samples of weekend and weekday shoppers were selected and the amount spent per trip to the mall was recorded as shown in the following table:
| Weekends |
Weekdays |
| n1 = 20 |
n2 = 20 |
| y-1 = $78 |
y-2 = $67 |
| s1 = $22 |
s2 = $20 |
a Is there sufficient evidence to claim that there is a difference in the average amount spent per trip on weekends and weekdays? Use α = .05.
b What is the attained significance level?