Conducts a permutation test to compare two groups for medians, percentiles, or proportion below a threshold value.
percentileTest(
formula = NULL,
data = NULL,
x = NULL,
y = NULL,
test = "median",
tau = 0.5,
type = 7,
threshold = NA,
comparison = "
A formula indicating the response variable and the independent variable. e.g. y ~ group.
The data frame to use.
If no formula is given, the response variable for one group.
The response variable for the other group.
The statistic to compare between groups. Can be
"median"
, "percentile"
, "iqr"
,
"proportion"
,
"mean"
, or "variance"
.
If "percentile"
is chosen as the test
,
tau
indicates the percentile to test. Expressed
as a quantile. That is, 0.5 indicates a test for medians.
0.75 indicates a test for 75th percentiles.
The type
value passed to the quantile
function.
If "proportion"
is chosen as the test
,
threshold
indicates the value of the dependent variable
to use as the threshold. For example, to test if there is a
different in the proportion of observations below $10,000,
threshold = 10000
would be used.
If "proportion"
is chosen as the test
,
comparison
indicates the inequality to use. Options are
"<"
, "<="
, ">"
, ">="
, or , "=="
The number of replicates in the permutation test.
The number of significant digits in the output.
If TRUE
, prints a dot for every 1 percent of
progress while conducting the test.
A list of three data frames with the data used, a summary for each group, and the p-value from the test.
The function will test for a difference in medians, percentiles, interquartile ranges, proportion of observations above or below some threshold value, means, or variances between two groups by permutation test.
The input should include either formula
and data
;
or x
and y
.
The function removes cases with NA in any of the variables.
If the independent variable has more than two groups, only the first two levels of the factor variable will be used.
The p-value returned is a two-sided test.
# NOT RUN {
data(BrendonSmall)
percentileTest(Sodium ~ Instructor,
data=BrendonSmall,
test="median")
percentileTest(Sodium ~ Instructor,
data=BrendonSmall,
test="percentile",
tau = 0.75)
percentileTest(Sodium ~ Instructor,
data=BrendonSmall,
test="proportion",
threshold = 1300)
# }
Run the code above in your browser using DataLab