foo is the data frame you provided mean(foo[1:25,2]) var(foo[1:25,2])
indexing key: foo[rows,cols] hth Stephen Sefick On Tue, Oct 20, 2009 at 11:04 AM, Sibusiso Moyo <sm...@vt.edu> wrote: > This is day one on R for me, I am trying to figure out how to do simple > computations. For example I have a data set with 200 observations. I am > trying to compute the mean and variance in r for 1:25 (first 25 > observations); 1:50 (first 50 obs) ; 1:100th observation etc. Here is the > dataset: > > Id value > 1 2.2338 > 2 3.13597 > 3 1.98685 > 4 4.35593 > 5 2.43963 > 6 4.20262 > 7 3.12131 > 8 4.79583 > 9 3.13937 > 10 3.47266 > 11 3.79954 > 12 4.32285 > 13 3.00058 > 14 1.26102 > 15 4.07329 > 16 3.42037 > 17 1.99195 > 18 5.4461 > 19 3.03448 > 2 2.63395 > 21 0.99851 > 22 > 4.59577 > 23 > 2.77719 > 24 > 4.82748 > 25 > 4.11373 > 26 > 2.38615 > 27 > 1.81247 > 28 > 0.920195 > 29 > 2.78129 > 30 > 3.10531 > 31 > 3.60793 > 32 > 1.66597 > 33 > 4.80673 > 34 > 4.80266 > 35 > 5.35791 > 36 > 2.44573 > 37 > 2.63854 > 38 > 4.13737 > 39 > 1.68496 > 40 > 3.86962 > 41 > 1.60028 > 42 > 4.35621 > 43 > 3.60847 > 44 > 2.38884 > 45 > 1.03786 > 46 > 5.48904 > 47 > 1.95086 > 48 > 2.75401 > 49 > 2.25081 > 50 > 3.46435 > 51 > 0.309484 > 52 > 2.49405 > 53 > 4.52522 > 54 > 1.17947 > 55 > 2.50136 > 56 > 1.74537 > 57 > 5.48072 > 58 > 1.81081 > 59 > 2.67793 > 60 > 4.40603 > 61 > 3.21767 > 62 > 2.68124 > 63 > 1.9723 > 64 > 1.25973 > 65 > 2.64177 > 66 > 3.28414 > 67 > 3.2394 > 68 > 4.07508 > 69 > 2.32812 > 70 > 3.42763 > 71 > 2.40944 > 72 > 2.43776 > 73 > 0.072419 > 74 > 6.29773 > 75 > 2.29704 > 76 > 6.07705 > 77 > 1.59146 > 78 > 4.74327 > 79 > 5.29088 > 80 > 4.17874 > 81 > 1.80639 > 82 > 3.70503 > 83 > 3.13294 > 84 > 5.44017 > 85 > 3.50002 > 86 > 2.1762 > 87 > 2.27356 > 88 > 4.45687 > 89 > 1.99272 > 90 > 3.74362 > 91 > 3.89474 > 92 > 0.93481 > 93 > 4.99464 > 94 > 1.02872 > 95 > 2.63587 > 96 > 3.85226 > 97 > 4.82513 > 98 > 1.1171 > 99 > 1.09368 > 100 > 3.91599 > 101 > 3.91832 > 102 > 1.81166 > 103 > 1.48144 > 104 > 5.24373 > 105 > 3.15134 > 106 > 3.03343 > 107 > 3.373 > 108 > 6.10409 > 109 > 4.84878 > 110 > 1.95195 > 111 > 2.25949 > 112 > 1.45546 > 113 > 3.60767 > 114 > 3.10228 > 115 > 3.22694 > 116 > 0.861855 > 117 > 3.93392 > 118 > 2.81212 > 119 > 1.62434 > 120 > 2.41149 > 121 > 4.42936 > 122 > 2.4765 > 123 > 0.979153 > 124 > 3.3482 > 125 > 1.20345 > 126 > 1.56576 > 127 > 5.1418 > 128 > 3.5585 > 129 > 3.21124 > 130 > 3.52901 > 131 > 2.38191 > 132 > 3.6129 > 133 > 3.56378 > 134 > 2.70181 > 135 > 0.355836 > 136 > 3.10734 > 137 > 6.22159 > 138 > 4.7172 > 139 > 2.88295 > 140 > 2.87566 > 141 > 2.01538 > 142 > 2.78835 > 143 > 2.26519 > 144 > 1.38217 > 145 > 2.63885 > 146 > 1.0584 > 147 > 1.93247 > 148 > 3.10316 > 149 > 2.24714 > 150 > 5.08326 > 151 > 2.21789 > 152 > 4.63046 > 153 > 3.90057 > 154 > 2.19171 > 155 > 5.46094 > 156 > 1.84918 > 157 > 1.04059 > 158 > 4.57513 > 159 > 5.06956 > 160 > 3.65212 > 161 > 1.14078 > 162 > 5.89406 > 163 > 2.86261 > 164 > 1.87261 > 165 > 4.47285 > 166 > 3.13892 > 167 > 1.59146 > 168 > 1.07166 > 169 > 2.82925 > 170 > 2.83742 > 171 > 5.13528 > 172 > 3.20376 > 173 > 1.56253 > 174 > 3.08726 > 175 > 3.52339 > 176 > 3.66837 > 177 > 2.70302 > 178 > 2.00471 > 179 > 3.6823 > 180 > 2.90728 > 181 > 2.39302 > 182 > 2.54367 > 183 > 3.98498 > 184 > 4.17124 > 185 > 1.99922 > 186 > 2.61908 > 187 > 2.24057 > 188 > 3.29836 > 189 > 2.59912 > 190 > 4.49458 > 191 > 1.44657 > 192 > 2.99004 > 193 > 5.15769 > 194 > 2.64342 > 195 > 1.81755 > 196 > 5.1977 > 197 > 4.10043 > 198 > 4.63281 > 199 > 3.20347 > 200 > 2.08211 > > ______________________________________________ > 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. > -- Stephen Sefick Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis ______________________________________________ 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.
