Table 1. Summary statistics for time-varying variables.

Individual-day variables	Mean (SD) or n (%)
Daily activity	0.01 (0.58)
Daily steps	11257.99 (5873.89)
Daily active minutes	43.75 (57.24)
Daily activity calories	952.10 (808.87)
In-study contacts’ average daily activity	0.03 (0.49)
In-study contacts’ average daily steps	11648.14 (5008.69)
In-study contacts’ average daily active minutes	46.65 (47.51)
In-study contacts’ average daily activity calories	996.41 (673.56)
Daily network size	10.28 (7.33)
Daily in bed minutes	370.06 (202.66)
Daily number of courses taken	2.50 (1.17)
Daily on campus status (1 = yes)	0.74 (0.10)
Number of cases	269,057 (100.00%)
Day variables
Weather indicators
Highest temperature (°F)	58.39 (19.56)
Lowest temperature (°F)	40.22 (16.69)
Precipitation in inch	0.12 (0.40)
Snowfall in inch	0.17 (0.80)
Snow piling depth in inch	0.44 (1.40)
Number of days	637 (100.00%)

Daily activity is a standardized factor score of 18 items, i.e., low range calories and minutes, fat burn calories and minutes, cardio calories and minutes, peak calories and minutes, steps, floors, sedentary minutes, lightly active minutes, fairly activity minutes, very active minutes, marginal calories, activity calories, calories BMR, and calories out.