Group Confidence Interval

Calculates the confidence interval of grouped data

group.CI(x, data, ci = 0.95)

Arguments

x

an `aggregate` compatible formula

data

a data frame (or list) from which the variables in formula should be taken

ci

the confidence interval to be calculated

Value

A data frame consisting of one column for each grouping factor plus three columns for the upper bound, mean and lower bound of the confidence interval for each level of the grouping factor

Examples

require(latticeExtra)
#> Loading required package: latticeExtra
with(group.CI(weight~feed,chickwts),
 segplot(feed~weight.lower+weight.upper,center=weight.mean)
)


require(Hmisc)
#> Loading required package: Hmisc
#> 
#> Attaching package: ‘Hmisc’
#> The following objects are masked from ‘package:plyr’:
#> 
#>     is.discrete, summarize
#> The following objects are masked from ‘package:base’:
#> 
#>     format.pval, units
with(group.CI(Temp~Month,airquality),
 xYplot(Cbind(Temp.mean,Temp.lower,Temp.upper)~numericScale(Month),type="b",ylim=c(60,90))
)