Discussion:
Q: Cash withdrawals (in multiples of $20) at an on-campus ATM for a random sample of 30 Fridays and 30 Mondays are shown below. At alpha = .01, is there a difference in the mean ATM withdrawal on Monday and Friday?
(a) Make stacked dot plots of the data (a sketch is OK).
(b) State the hypotheses.
(c) State the decision rule and sketch it.
(d) Find the test statistic.
(e) Make a decision.
(f) Find the p-value and interpret it.
Randomly Chosen ATM Withdrawals ($)
Friday Monday
250 10 10 40 30 10
20 10 30 100 70 370
110 20 10 20 20 10
40 20 40 30 50 30
70 10 10 200 20 40
20 20 400 20 30 20
10 20 10 10 20 100
50 20 10 30 40 20
100 20 20 50 10 20
20 60 70 60 10 20