
Hi,

I am trying to calculate confidence intervals using ci.numeric from epicalc package. If I generate a normal set of data and find the 99% and 95% CI, they seem too narrow to me. Am I doing something wrong?? The IQR goes from -0.62 to 0.62, so I thought the CI limits should be more extreme than these values.

 x<- rnorm(200,0,1)
ci.numeric(x=mean(x),n=200,sds=sd(x),alpha=0.05)
    n        mean       sd         se  lower95ci upper95ci
1 200 -0.07129813 1.015668 0.07181859 -0.2129213 0.0703250

ci.numeric(x=mean(x),n=200,sds=sd(x),alpha=0.01)
   n        mean       sd         se  lower99ci upper99ci
 200 -0.07129813 1.015668 0.07181859 -0.2580811 0.1154848

quantile(x)
         0%         25%         50%         75%        100% 
-3.23354673 -0.61926758 -0.06672757  0.62000897  2.43763696

Thanks,

D.
 		 	   		  
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