Hello,
If you have a numeric matrix or data.frame, try something like
cov(mtcars)
Hope this helps,
Rui Barradas
Às 10:15 de 04/10/2024, Steven Yen escreveu:
On 10/4/2024 5:13 PM, Steven Yen wrote:
Pardon me!!!
What makes you think this is a homework question? You are not
obligated to respond if the question is not intelligent enough for you.
I did the following: two ways to calculate a covariance matrix but
wonder how I might replicate the results with "apply". I am not too
comfortable with the online documentation of "apply".
set.seed(122345671) > n<-3 > x<-rnorm(n); x [1] 0.92098449 0.80940115
0.60374785 > cov1<-outer(x-mean(x),x-mean(x))/(n-1); cov1 [,1] [,2]
[,3] [1,] 0.0102159207 0.00224105983 -0.0124569805 [2,] 0.0022410598
0.00049161983 -0.0027326797 [3,] -0.0124569805 -0.00273267965
0.0151896601 > cov2<-(x-mean(x))%*%t((x-mean(x)))/(n-1); cov2 [,1]
[,2] [,3] [1,] 0.0102159207 0.00224105983 -0.0124569805 [2,]
0.0022410598 0.00049161983 -0.0027326797 [3,] -0.0124569805
-0.00273267965 0.0151896601 >
On 10/4/2024 4:57 PM, Uwe Ligges wrote:
Homework questions are not answered on this list.
Best,
Uwe Ligges
On 04.10.2024 10:32, Steven Yen wrote:
The following line calculates standard deviations of a column vector:
se<-apply(dd,1,sd)
How can I calculate the covariance matrix using apply? Thanks.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Este e-mail foi analisado pelo software antivírus AVG para verificar a presença
de vírus.
www.avg.com
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide https://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
