Describe Relationship: Categorical y vs Numeric x

Computes descriptive statistics for the relationship between a categorical variable y and a numeric variable x.

Usage

.descQN(y, x, conf.level = 0.95, breaks, right)

# S3 method for class 'Desc.qn'
print(x, verbose = NULL, ...)

Arguments

x

a numeric variable

verbose

amount of printed output

...

further arguments passed to methods

y

a categorical variable (factor or coercible to factor)

conf.level

confidence level for interval estimates (default 0.95)

breaks

numeric vector defining cut points for x. If not supplied, quartiles of x are used.

right

logical; passed to cut(), defining interval closure

Value

an object of class c("Desc.qn", "Desc") with components:

grpTable

group-wise summary table

kw

result of the Kruskal-Wallis test

eta2

effect size

levene

result of Levene's test

tauB

estimate, confidence interval, and p-value for Kendall's tau-b

spearman

estimate, confidence interval, and p-value for Spearman's correlation

auc

area under the curve for a binary outcome

prevTable

prevalence table for a binary outcome with columns:

quantile

quantile group

n

number of complete cases in the group

est

point estimate of the prevalence

lci

lower confidence interval bound

uci

upper confidence interval bound

caTest

result of the Cochran-Armitage test for a binary outcome

Details

The function summarizes how a numeric variable x differs across levels of a categorical variable y.

Computed statistics

• Group-wise descriptive statistics (median, IQR, counts)

• Kruskal-Wallis test with effect size (\(\eta^2\))

• Levene's test for homogeneity of variance

• Kendall's Tau-b with confidence interval and p-value

• Spearman correlation (reported for higher verbosity levels)

Binary outcomes If y has two levels:

• Area under the curve (AUC)

• Prevalence across quantile groups of x

• Cochran-Armitage trend test

Quantile grouping The numeric variable x is optionally discretized using breaks. By default, quartiles are used.

See also

desc(), desc.nn(), desc.nq(), kruskal.test(), lumen::leveneTest()

Other desc: desc(), desc.Date(), desc.factor(), desc.nn, desc.nq, desc.numeric(), desc.qq, desc.table(), desc.ts()