Table 1.

Summary of time-varying variables.

Variables for each individual each day	Mean (SD) or n (%)
Daily mean heart beats per minute	74.41 (9.69)
Daily standard deviation of heart beats per minute	15.33 (4.28)
In-study contacts’ average daily mean heart beats per minute	74.85 (8.39)
In-study contacts’ average daily standard deviation of heart beats per minute	15.71 (3.70)
Daily network size	10.06 (7.17)
Daily physical activity	0.02 (0.58)
Daily minutes in bed	378.02 (197.41)
Daily number of courses taken (during regular school days)	2.51 (1.16)
Number of cases	208,074 (100.00%)
Variables for each day
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%)