Question

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 σ = 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.

Q61: The appropriate statistical procedure for this example would be a

• A.z-test
• B.t-test

Q62: Is this a one-tailed or a two-tailed test?

• A.one-tailed
• B.two-tailed

Q63: The most appropriate null hypothesis (in words) would be

• A. There is no statistical difference in the amount of time appendix patients spend in the hospital when comparing the new recovery program to the population of patients on the traditional recovery program.
• B. There is a statistical difference in the amount of time appendix patients spend in the hospital when comparing the new recovery program to the population of patients on the traditional recovery program.
• C. The new appendix recovery program does not significantly reduce the number of days spent in the hospital when compared to the population of patients on the traditional recovery program.
• D. The new appendix recovery program does significantly reduce the number of days spent in the hospital when compared to the population of patients on the traditional recovery program.

Q64: The most appropriate null hypothesis (in symbols) would be

• A. μ_{new program} = 6.3
• B. μ_{new program} = 5.5
• C. μ_{new program} 6.3
• D. μ_{new program} 6.3

Q65: Set up the criteria for making a decision. That is, find the critical value using an

alpha = .01. (Make sure you are sign specific: + ; - ; or ) (Use your tables)

Answer 1

Q61: The appropriate statistical procedure for this example would be a

is z test since sigma is known

• A.z-test

Q62: Is this a one-tailed or a two-tailed test?

its a left tail z test for mean

• A.one-tailed

Q63: The most appropriate null hypothesis (in words) would be

The new appendix recovery program does not significantly reduce the number of days spent in the hospital when compared to the population of patients on the traditional recovery program.

Q64: The most appropriate null hypothesis (in symbols) would be

since popualtion mean is 6.3,we define null hypothesis for population mean

Ho:mu=6.3

Q65: Set up the criteria for making a decision. That is, find the critical value using an

alpha = .01

=NORM.S.INV(0.01)

=-2.326347874

if test statistic is less than the critical value reject null hypothesis

if t<-2.3263,reject Ho

if t>-2.3263 ,fail to reject Ho