# score.transform: Function for transforming scores onto different scales In CTT: Classical Test Theory Functions

## Description

The function transforms the score metric by setting new scales' mean, standard deviation, and normalizing the distribution.

## Usage

 `1` ```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

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13``` ```# 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) ```

CTT documentation built on May 2, 2019, 1:08 p.m.