DAAGxtras (version 0.6-9)

excessRisk: Create and analyze multiway frequency or weighted frequency table

Description

This function creates a multi-way table of counts for the response given a set of classifying factors. Output facilitates a check on how the factor specified as margin may, after accounting for other classifying factors, affect the response.

Usage

excessRisk(form = weight ~ seatbelt + airbag, response
= "dead", margin = "airbag", data = nassCDS, decpl = 4,
printResults=TRUE)

Arguments

form

form is a formula in which classifying factors appear on the right, with an optional weight variable on the left.

response

response is a binary variable or two-level factor such that the response of interest is the relative number in the two levels.

margin

margin is the factor whose effect on the response, after accounting for other classifying factors, is of interest

data

data is a data frame in which variables and factors may be found

decpl

decpl is the number of decimal places in proportions that appear in the output

printResults

if TRUE, a tabular summary is printed.

Value

• The function returns a data frame, with one row for each combination of levels of factors on the right of the formula, but excluding the factor specified as margin
• Count for level 2 of response & level 1 of margin
• Total tount for level 1 of margin
• Count for level 2 of response & level 2 of margin
• Total count for level 2 of margin
• Proportion; divide count for level 1 or margin by total
• Proportion; divide count for level 2 or margin by total
• Excess count for level 2 of response in that row; relative to the assumption that, in that row, there is no association between response and margin. (For the airbag data; this column gives excess deaths due to airbags, with negative values favouring airbags.)

Details

The best way to understand what this function does may be to run it with the default parameters, and/or with examples that appear below.

References

See help(nassCDS)

See Also

xtabs

Examples

excessRisk()
excessRisk(weight ~ airbag+seatbelt+dvcat)
UCB <- as.data.frame.table(UCBAdmissions)
excessRisk(Freq~Gender, response="Admit", margin="Gender",data=UCB)
excessRisk(Freq~Gender+Dept, response="Admit", margin="Gender",data=UCB)