[R] Generation of Normal Random Numbers

[Michael Bedward]

m <- c(1004.1, 1028.3, 1044.3, 861.4)
s <- c(194.5899, 158.7052, 123.3000, 285.8695)
x <- mapply(function(mi, si) rnorm(25, mi, si), m, s)

Hope this helps,

Michael


On 11 January 2011 17:44, saggak <saggak1908 at yahoo.co.in> wrote:
> Dear R helpers
>
> I have a data frame as given below
>
> df = data.frame(A = c(776,827,836,995,855,1026,1203,1363,965,1195),
>                        B = c(806,953,1049,1056,1243,764,1148,1162,948,1154),
>                        C = c(959,1155,1193,1163,863,1070,1087,877,1132,944),
>                        D = c(906,760,978,1170,1009,883,1007,960,828,113))
>
> # Actually the real data has number of vectors and not only A, B, C and D.
>
> m = as.numeric(lapply(df, mean))
> s = as.numeric(lapply(df, sd))
>
> gives
>
>> m
> [1] 1004.1 1028.3 1044.3  861.4
>> s
> [1] 194.5899 158.7052 123.3000 285.8695
>
> I need to generate 25 (normal) random numbers for each of these mean and corresponding standard deviation combination (m[i], s[i]). i.e. I need to have a table (dim 25 X  4) giving me random numbers.
>
>
> rnorm(25, m[1], s[1])   rnorm(25, m[2], s[2])   rnorm(25, m[3], s[3])  rnorm(25, m[4], s[4])
>    ....................           .........................           ...............                 .................
>    ....................           .........................           ...............                 .................
>    ....................           .........................           ...............                 .................
>    ....................           .........................           ...............                 .................
>
>
>    ....................           .........................           ...............                 .................
>
>
> Kindly guide
>
>
> Thanking in advance
>
> Sagga K
>
>
>
>
>
>
>
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>
>
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