A+ Answers

1. At an office of transcription workers at a large hospital, it is common for a transcriber to type without a break for up to 3 hours. It was decided to test the effects of ergonomically designed work stations (i.e., properly adjusted and fitted office chairs, adjustable computer keyboards, and wrist rests) on the length of time before feeling uncomfortable or fatigued in the upper extremities, neck, and back. Two groups of nine employees were recruited. One group was given the ergonomically designed workstations and the other group used the existing non-ergonomically designed workstations. All were followed for five working days and asked to note when they began to feel uncomfortable or fatigued. The data below represent the time it took (in minutes) for each subject to report feeling uncomfortable in the upper extremities, averaged over the five days.

Ergonomic Work Station (Group A) Non-Ergonomic Work Station (Group B)
32        35
37        31
35        29
28        25
41        34
35        27
31        32
33        31
44        40

Report the following: (Note: Round answers for means and standard deviations to two decimal places!)

What specific statistical analysis did you run to compare these means?

What was the p-value or significance?

Would you accept or reject the null hypothesis?

2. You work in a setting with individuals who have sports related injuries. You are interested in determining if icing with elevation is an effective treatment in reducing swelling following an ankle sprain. You’ve recruited 12 individuals with ankle sprains and pretested for edema using a tape measure to give an ankle circumference score in mm. After 2 days, measurements were recorded again. The data are as follows:

Pre       Post
100      89
99        79
113      103
97        90
109      103
102      96
109      82
101      92
115      107
96        98
94        78
101      83

Report the following: (Note: Round answers for means and standard deviations to two decimal places!)

What specific statistical analysis did you run to compare these means?

What was the p-value or significance?

Would you accept or reject the null hypothesis?

3. In a clinic, patients are commonly seen with frozen shoulder syndrome, a painful condition limiting active and passive range of motion. Because range of motion, as measured goniometrically, is commonly used to show improvement, you decided that you and your two colleagues should establish that you are all performing these measurements in a consistent and reliable manner. The data below represent goniometer measurements in degrees of shoulder abduction in the same 10 patients as taken by the three different therapists.

Clinician 1      Clinician 2      Clinician 3
35        50        42
45        47        30
56        40        22
66        75        90
72        60        55
79        80        65
80        50        76
100      110      55
124      126      44
178      171      102


Report the following: (Note: Use Excel to determine the means and standard deviations and round answers for means and standard deviations to two decimal places!

What specific statistical analysis did you run to compare these means?

What was the p-value or significance?

Would you accept or reject the null hypothesis?