Coffee, depression, and physical activity. Caffeine is the world’s most widely used stimulant, with approximately 80% consumed in the form of coffee. Participants in a study investigating the relationship between coffee consumption and exercise were asked to report the number of hours they spent per week on moderate (e.g., brisk walking) and vigorous (e.g., strenuous sports and jogging) exercise. Based on these data the researchers estimated the total hours of metabolic equivalent tasks (MET) per week, a value always greater than 0. The table below gives summary statistics of MET for women in this study based on the amount of coffee consumed.
| Caffeinated coffee consumption | ||||||
| 1 cup/week | 2-6 cups/week | 1 cup/day | 2-3 cups/day | 4 cups/day | Total | |
| Mean | 18.7 | 19.6 | 19.3 | 18.9 | 17.5 | |
| SD | 21.1 | 25.5 | 22.5 | 22.0 | 22.0 | |
| n | 12,215 | 6,617 | 17,234 | 12,290 | 2,383 | 50,739 |
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Write the hypotheses for evaluating if the average physical activity level varies among the different levels of coffee consumption.
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Check conditions and describe any assumptions you must make to proceed with the test.
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Below is part of the output associated with this test. Fill in the empty cells.
Df Sum Sq Mean Sq F value Pr(F) coffee XXXXX XXXXX XXXXX XXXXX 0.0003 Residuals XXXXX 25,564,819 XXXXX Total XXXXX 25,575,327 -
What is the conclusion of the test?