MA207 Final Exam - Takehome Portion
For each of the problems below, use the technology guide to perform a statistical analysis.
You should justify your choice of method, including any assumptions made in the use of the method.
You should indicate whether a two-tailed, left-tailed, or right-tailed analysis is appropriate,
and, in hypothesis testing problems, state the null and alternative hypotheses.
If the problem does not specify a level of significance, you should choose one.
Problem 1
A new technique for gall bladder surgery is intended to shorten the length of stay. In a comparitive study, 48 surgical patients are treated with the new technique and have an average stay of 3.9 days with a standard deviation of 0.8 days,
while a second group of 67 patients is treated with the traditional technique. If the second group has an average stay of 4.4 days with a standard deviation of 0.9 days, can we conclude on the basis of this study that the new technique is effective in reducing length of stay?
Problem 2
Nationwide, General Adult Inpatient Psychiatric Care units average 8.3 staff hours per day for each patient with a standard deviation of 2.4. An audit of records for 72 patients produces an average of 7.9 staff hours per day. Based on this data,
can you conclude that this hospital provides fewer staff hours per day than the national average?
Problem 3
Nationwide statistics for alchohol rehabilitation facilities show that after 4 weeks of
treatment, 37% of patients manage to remain abstinent for 6 weeks. Out of 48 patients released from a certain alchohol rehabilitation clinic, after 6 weeks only 12 remain abstinent. Can we
conclude statistically that this particular clinic does not perform as well as the national average?