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. Author manuscript; available in PMC: 2018 Nov 1.
Published in final edited form as: Psychol Aging. 2017 Oct 12;32(7):642–653. doi: 10.1037/pag0000198

Table 1.

Descriptive Statistics of the Daily Alcohol Use, Sleep Duration, and Next-day Tiredness Variables for Younger and Older Age Groups

Intraindividual Means and Standard Deviations Intraindividual Correlation

iMean (SD) iSD (SD) Alcohol Sleep
Younger Adults (n = 91)

Alcohol (drinks) 0.64 (0.52) 1.19 (0.72) --
Sleep (hours) 7.20 (0.68) 1.27 (0.38) −0.11 [−0.53, 0.23] --
Tiredness (0 to 7) 3.29 (0.81) 1.10 (0.30) 0.07 [−0.20, 0.46] −0.36 [−0.81, 0.01]

Older Adults (n = 75)

Alcohol 0.61 (0.63) 0.61 (0.36) --
Sleep 7.06 (0.84) 0.68 (0.27) −0.03 [−0.33, 0.35] --
Tiredness 2.19 (0.93) 0.68 (0.28) −0.01 [−0.26, 0.29] −0.30 [−0.77, 0.09]

Notes: iMean = intraindividual mean; iSD = intraindividual standard deviation; SD = sample-level standard deviation. Alcohol use is reported in number of drinks (1 drink = 14 grams alcohol). Correlation matrices for each age group contain the average intraindividual correlation, and the range of those correlations in brackets [min, max].