Patients recovering from an appendix operation normally spend an average of 6.3 days in the hospital. The distribution of recovery times is normal with a standard deviation of 2.2 days. The hospital is trying a new recovery program designed to lessen the time patients spend in the hospital. The first 25 appendix patients in this new program were released from the hospital in an average of 5.5 days. On the basis of these data, can the hospital conclude that the new program has a significant reduction of recovery time. Test at the .01 level of significance.

Set up criteria for making a decision. That is, find the critical value using an alpha = .01.

What is the numeric value of your standard error?

What is the z-value or t-value you obtained (your test statistic)?

Based on the results (and comparing your Q67 and Q65 answers) would you reject the null hypothesis or fail to reject the null hypothesis?