eq {lazy.tools} R Documentation

## Observed Score Equating

### Description

This performs the observed score equating of the test score 1 to the test score 2.

```eq(
score1,
freq1,
cdf1 = NULL,
score2,
freq2,
cdf2 = NULL,
lim1 = NULL,
lim2 = NULL,
smooth1 = 0,
bandwid1 = 3,
smooth2 = 0,
bandwid2 = 3,
method = 2,
title = "",
nolow = 0,
round = 1,
print = 1,
plot = 1
)
```

### Arguments

 `score1` a vector consisting of the score of test1 `freq1` a vector consisting of the frequency counts at score1 `cdf1` a vector consisting of the cumulative frequencies at score1 `score2` a vector consisting of the score of test2 `freq2` a vector consisting of the frequency counts at score2 `cdf2` a vector consisting of the cumulative frequencies at score2 `lim1` min and max score of test1 `lim2` min and max score of test2 `smooth1` # of times to smooth cdf1 `bandwid1` bandwidth for running average smooth of cdf1 `smooth2` # of times to smooth cdf2 `bandwid2` bandwidth for running average smooth of cdf2 `method` = 1 to use linear equating = 2 to use equi-percentile equating `title` title string `nolow` = 1 to avoid lowering scores `round` = 0 not to round the result to integer. (not yet available) `print` = 1 to print the result `plot` = 1 to plot the conversion table = 2 to plot the cdf = 3 to plot the smoothed cdf

### Details

Equipercentile equating is essentially the same as qqplot.
Therefore, the following two codes produce similar results:
`eq( score1=score1, freq1=freq1, score2=score2, freq2=freq2 )`
``` qqplot( expand_freqdist( score1, freq1 ) , expand_freqdist( score2, freq2 ), type="l" ) ```
Note that, since native qqplot cannot handle case weight, expand_freqdist is used to recover the raw data from frequency table.

### Value

a list of the following:
ctable: the conversion table consisting of (score, score21, freq1)
mands: the summary stat of the converted score dist: (score21,freq1)
newfreq: the frequency distribution of the converted score (score21, freq21)
sdist1 and sdist2: input and smoothed score distributions
cntr: a list of control parameters used.

### Examples

```
seed <- 1701
set.seed(seed)

scoredist1 <- gen_test_score( 500, 0,10, beta=c(2,4), plot=1 )
scoredist2 <- gen_test_score( 1000, 0,15, beta=c(4,2), plot=1 )
reseq <- eq( score1=scoredist1[,1], freq1=scoredist1[,2]
, score2=scoredist2[,1], freq2=scoredist2[,2]
, smooth1=3, smooth2=3, method=2, plot=3 )

```

[Package lazy.tools version 0.1.3 Index]