That is very helpful, and exactly what I was looking for! However, I seem to have some problems. When I ran the following line:
aggregate(SunScore ~ h, data=dat, mean) I got the following output: h SunScore 1 0 136.01389 2 1 135.27632 3 2 127.03704 4 3 127.17105 5 4 129.94545 6 5 113.70909 7 6 111.49020 8 7 109.51020 9 8 98.03922 10 9 88.40000 11 10 72.57407 12 11 63.41333 13 12 68.36170 14 13 68.28571 15 14 77.47761 16 15 93.18056 17 16 108.78161 18 17 112.39759 19 18 126.17241 20 19 126.98901 21 20 134.03896 22 21 131.48611 23 22 135.06024 24 23 136.02247 But when I do the averages by hand, I get different numbers. When I calculated the average of the scores from 0:00 to 0:59, I got a score of 131.01667. However, R says the average for the same time period is 136.01389. Why are these numbers so different? And how can I fix it? -- View this message in context: http://r.789695.n4.nabble.com/Questions-about-doing-analysis-based-on-time-tp4634230p4634745.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.