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?