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!) a. Group A Mean: 35.11 b. Group B Mean: 31.56 c. Group A Standard Deviation: 4.99 d. Group B Standard Deviation: 4.48 What specific statistical analysis did you run to compare these means? A t-test looks at the difference in means of a continuous variable between two groups. Remember that the null hypothesis Ho has no difference in the means (i.e., µ1= µ2) and the alternative hypothesis has a difference in the means. Remember that the p-value (significant at <0.05) is the probability that you would find the answer you have (i.e. the difference in means) given that the null hypothesis is true. 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. Youve 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 83Report the following: (Note: Round answers for means and standard deviations to two decimal places!)a. Pre Treatment Mean: b. Post Treatment Mean: c. Pre Treatment Standard Deviation: d. Post Treatment Standard Deviation: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?
