A sales manager for a large department store believes that customer spending per visit with a sale is lower than customer spending without a sale, and would like to test that claim. A simple random sample of customer spending is taken from without a sale and with a sale. The results are shown below.

Without Sale With Sale

Mean 82.904 71.316

Variance 1984.96 1826.41

Observations 200 150

Hypothesized Mean Difference 0

df 328

t Stat -2.465

P(T<=t) one-tail 0.0071

t Critical one-tail -1.65

P(T<=t) two-tail 0.0142

t Critical two-tail -1.967

Confidence Level 99%

Samples from without sale: nwithout=

Point estimate for spending without sale: xwithout=

Samples from with sale: nwith=

p=

Point estimate for spending with sale: xwith=

t=