[R] trouble using boot package
lhill at ipimar.pt
Fri Jun 25 17:48:03 CEST 2004
I am trying to carry out a bootstrap analysis (using the boot package) on a
table and cannot work out how to get the results I need!
I have a table ("d2") with 4 columns: "ID_code", "Age", "Quarter" and
"StomWt". Age (0-5) and Quarter (1-4) are my strata
Therefore I wish to estimate the confidence intervals for the mean StomWt
for each Age and Quarter.
If I do this manually for each age / quarter I get the following:
> boot (d2$StomWt[d2$Age=="0" & d2$Quarter=="1"], mean, R=999)
ORDINARY NONPARAMETRIC BOOTSTRAP
boot(data = d2$StomWt[d2$Age == "0" & d2$Quarter == "1"], statistic = mean,
R = 999)
Bootstrap Statistics :
original bias std. error
t1* 3.365 0 0
Firstly - shouldn't the bias and std error be something other than 0?
Furthermore, I would like to know if there is a way (function?) I can use
that would automate this?
Thank you for your help
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