The credit manager for Braxton's Department Store, in examining the accounts for various types of customers served by the establishment, has noticed that the mean outstanding balance for a sample of 20 customers from the local zip code is $375, with a standard deviation of $75. For a sample of 25 customers from a nearby zip code, the mean and standard deviation were $425 and $143, respectively.
Assuming normal populations and using the 0.05 level of significance, examine whether credit customers from the two zip codes might have the same mean outstanding balance. What is the most accurate statement that could be made about the p-value for this test?
Construct and interpret the 95% confidence interval for the difference between the population means. Is the hypothesized difference (0.00) within the interval? Given the presence or absence of the 0.00 value within the interval, is this consistent with the findings of the hypothesis test?