# percentages: Easy Creation of Tables of Percentages In memisc: Management of Survey Data and Presentation of Analysis Results

## Description

The generic function `percentages` and its methods create one- or multidimensional tables of percentages. As such, the function `percentages` can be viewed as a convenience interface to `prop.table`. However, it also allows to obtain standard errors and confidence intervals.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```percentages(obj, ...) ## S3 method for class 'table' percentages(obj, by=NULL, which=NULL, se=FALSE, ci=FALSE, ci.level=.95, ...) ## S3 method for class 'formula' percentages(obj, data=parent.frame(), weights=NULL, ...) ## S3 method for class 'percentage.table' as.data.frame(x, ...) ## S3 method for class 'xpercentage.table' as.data.frame(x, ...) ```

## Arguments

 `obj` an object; a contingency table or a formula. If it is a formula, its left-hand side determines the factor or combination of factors for which percentages are computed while its right-hand side determines the factor or combination of factors that define the groups within which percentages are computed. `by` a character vector with the names of the factor variables that define the groups within which percentages are computed. Percentages sum to 100 within combination of levels of these factors. `which` a character vector with the names of the factor variables for which percentages are computed. `se` a logical value; determines whether standard errors are computed. `ci` a logical value; determines whether confidence intervals are computed. Note that the confidence intervals are for infinite (or very large) populations. `ci.level` a numerical value, the required confidence level of the confidence intervals. `data` a contingency table (an object that inherits from "table") or a data frame or an object coercable into a data frame. `weights` an optional character string with the name of a variable containing weights. `x` an object coerced into a data frame. `...` Further arguments, ignored.

## Value

An array that inherits classes "percentage.table" and "table". If `percentages` was called with `se=TRUE` or `ci=TRUE` then the result additionally inherits class "xpercentage.table".

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29``` ```# Two equivalent ways to create the same table 100*prop.table(UCBAdmissions) percentages(UCBAdmissions) # Three equivalent ways to create the same table 100*prop.table(UCBAdmissions,c(2,3)) (p0 <- percentages(UCBAdmissions,by=c("Gender","Dept"))) percentages(UCBAdmissions,which="Admit") # Percentage table as data frame as.data.frame(p0) # Three equivalent ways to create the same table 100*prop.table(margin.table(UCBAdmissions,c(1,2)),2) percentages(UCBAdmissions,which="Admit",by="Gender") percentages(Admit~Gender,data=UCBAdmissions) # Three equivalent ways to create the same table 100*prop.table(margin.table(UCBAdmissions,c(1,3)),2) percentages(Admit~Dept,data=UCBAdmissions) percentages(Admit~Dept,data=as.data.frame(UCBAdmissions), weights="Freq") # Standard errors and confidence intervals percentages(Admit~Dept,data=UCBAdmissions,se=TRUE) percentages(Admit~Dept,data=UCBAdmissions,ci=TRUE) (p<- percentages(Admit~Dept,data=UCBAdmissions,ci=TRUE,se=TRUE)) # An extended table of percentages as data frame as.data.frame(p) ```

memisc documentation built on Dec. 23, 2017, 5:09 p.m.