score.transform {CTT} | R Documentation |
Function for transforming scores onto different scales
Description
The function transforms the score metric by setting new scales' mean, standard deviation, and normalizing the distribution.
Usage
score.transform(scores, mu.new = 0, sd.new = 1, normalize = FALSE)
Arguments
scores |
Vector for examinee scores |
mu.new |
Desired mean of the scale |
sd.new |
Desired standard deviation of scales |
normalize |
If normailize=True, the score will be normalized applying the inverse of the cumulative distribution function of the normal distribution to the respondents percentile score. |
Value
The function returns a list with two vectors: new.scores is the transformed score and p.scores is the percentile rank of every examinee. If normalize=TRUE than percentile scores are used to create a roughly normal distribution by applying an inverse cumulative normal distribution function to the p.scores.
Author(s)
John T. Willse, Zhan Shu
Examples
# Example data provided with package
data(CTTdata)
data(CTTkey)
# Data scored to demonstrate function
scores <- score(CTTdata,CTTkey)$score # obtain the scores
# the targeted mean=3, standard deviation=1
score.transform(scores,3,1)
# the score should be transformed by normalized precentile
score.transform(scores,3,1,TRUE)
[Package CTT version 2.3.3 Index]