Question 1

A study was undertaken to determine whether there was a significant weight (in lb) loss after one year course of therapy for diabetes, and whether the amount of weight (in lb) loss was related to initial weight. The following table gives the initial weight (x) and weight after one year of therapy (y) for 16 newly diagnosed adult diabetic patients.

Subject	x	y
1	140	115
2	160	130
3	180	135
4	120	125
5	132	112
6	146	130
7	190	160
8	200	160
9	120	123
10	145	143
11	150	125
12	160	140
13	160	135
14	149	120
15	129	119
16	150	130

1. Is a one-sided or two-sided test needed here?

2. What is the mean weight for each time period?

3. What is the standard deviation for each time period?

4. Carry out the hypothesis test(s) in question in above d. Use =0.01

Appropriate test:

Hypotheses:

Null:

Alt:

The critical value:

The test statistics:

Decision about null hypothesis and findings/ Conclusion:

5. Are the means statistically different?

6. Find the 99% confidence interval for the difference of the two means on weight. Interpret your finding.

99% Confidence interval for the difference:

7. Which statistical test is appropriate to use on these data?

Question 2

Delays in discharges from immediate health care facilities create unnecessary risks of expenses for patients and their families. Discharge delays (in days) from two healthcare facilities are shown in the following table. Assume that these data represent SRSs from their respective populations and that the populations demonstrate no major departure from normality.

Facility A	12	9	13	16	7	19	20	16	15	14	12	16
facility B	7	10	13	15	9	15	12	16	8	9	6	12

1. Find the mean, median, variance and standard deviation of delays times for Facility A.

2. Find the mean, median, variance and standard deviation of delays times for Facility B.

3. Compare delays times in the facilities and test whether there was significant difference in mean delay times? Use alpha=0.05

Hypotheses:

Null:

Alt:

The critical value:

The test statistics:

Decision about null hypothesis and findings/ Conclusion: