Reference no: EM132848173
Part I. Study Methods and Basic Statistics
Background
Assume you are trying to refine physical activity recommendations for young adults. You and your research team decide to collect a small sample of pilot data on physical activity (PA) habits to determine how often young adults should exercise (frequency) to correspond to achieve the recommended 1000 kcal/week physical activity energy expenditure. You collected information on self-reported physical activity by the Paffenbarger Exercise Habits Questionnaire (Paffenbarger et al., 1993) on a group of master's students. Deidentified data from this survey is available below.
Subject ID PA Bouts per Week 5 or More Bouts per Week PA Energy Expenditure
1 6 yes 1310
2 5 yes 3058
3 7 yes 5676
4 3 no 1378
5 5 yes 3837
6 2 no 1658
7 0 no 1417.5
8 4 no 1998
9 6 yes 4433
10 6 yes 9750
11 5 yes 3932
12 5 yes 2020
13 3 no 4324
14 7 yes 6375
15 7 yes 10976
16 7 yes 9632
17 4 no 926
18 7 yes 7168
19 5 yes 2182
20 3 no 3299
21 4 no 2566
22 3 no 1826
23 5 yes 2168
24 5 yes 1904
25 7 yes 7336
26 4 no 984
27 4 no 928
28 7 yes 3774
29 4 no 2108
30 4 no 2500
Kilocalories per Week
a. Complete the stem-and-leaf plot below (type values beside the appropriate range on the lines provided; see example in section a.
(0-999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(1000-1999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(2000- 2099) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(3000- 3999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(4000- 4999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(5000- 5999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(6000- 6999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(7000- 7999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(8000- 8999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(9000- 10000) | ___ ___ ___ ___ ___ ___ ___ ___ ___
(10000- 10999) | ___ ___ ___ ___ ___ ___ ___ ___ ___
b. Calculate measures of central tendency.
Mean:
Median:
Mode:
c. Calculate measures of variability (SD has already been calculated for you - I'm not that mean =)
Standard Deviation: 2,805 kcal/week
Range:
IQR:
d. Are there clear outliers? Does the data appear to be skewed? Compare the mean and median - are they similar? Would you use parametric or nonparametric methods to study 'kcals/week' as an outcome?