IRS Tax Return Help The local branch of the Internal Revenue Service spent an average of 21 minutes helping each of 10 people prepare their tax returns.
The standard deviation was 5.6 minutes. A volunteer tax preparer spent an average of 27 minutes helping
10. Hospital Stays for Maternity Patients Health Care Knowledge Systems reported that an insured woman spends on average 2.3 days in the hospital for a routine childbirth, while an uninsured woman spends on average 1.9 days. Assume two samples of 16 women each were used in both samples. The standard deviation of the first sample is equal to 0.6 day, and the standard deviation of the second sample is 0.3 day. At a = 0.01, test the claim that the means are equal. Find the 99% confidence interval for the differences of the means. Use the P-value method.
Source: Michael D. Shook and Robert L. Shook, The Book of Odds.