[R] descriptive statistics qn

[stephen sefick]

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 <smoyo at 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
>
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>



-- 
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