Table 5: Probability Density Functions for the NREL May Data Set, given by hour.

Hour Mean σ/S Distribution R2
0 -0.0123 0.0136 Logistic -
1 -0.0094 0.0127 Logistic -
2 -0.0085 0.0122 Logistic -
3 -0.0054 0.0118 Logistic -
4 -0.0038 0.0076 Logistic -
5 -0.0035 0.0078 Logistic -
6 -0.0123 0.0136 Logistic -
7 0.0188 0.0236 Normal 0.9663
8 0.0630 0.0435 Normal 0.9753
9 0.1050 0.0591 Normal 0.9858
10 0.1320 0.0758 Normal 0.9819
11 0.1387 0.0975 Normal 0.9799
12 0.1424 0.1028 Normal 0.9723
13 0.2341 1.2536 Normal 0.7359
14 0.1222 0.0961 Normal 0.9584
15 0.0917 0.0773 Normal 0.9789
16 0.0600 0.0600 Normal 0.9539
17 0.0272 0.0356 Normal 0.9382
18 -0.0053 0.0164 Logistic 0.9487
19 -0.0061 0.0374 Logistic 0.7833
20 -0.0049 0.0224 Logistic 0.8150
21 -0.0083 0.0254 Logistic 0.6083
22 -0.0084 0.0205 Logistic 0.8979
23 -0.0117 0.0143 Logistic 0.8055