ppass_par_and_fit.Rmd

---
title: Analyzing a dataset
author: Manuel Reif
output:
  prettydoc::html_pretty:
    theme: cayman
    highlight: github
---
<!--
%\VignetteEngine{knitr::rmarkdown}
%\VignetteIndexEntry{Analyzing a dataset}
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# Analyzing a simulated data set


```{r loadall}

library(PP)
library(data.table)

```

## First example

```{r simulate_data1}
suppressWarnings(RNGversion("3.5.0"))
set.seed(1526)

# intercepts
diffpar <- seq(-3.6,3,length=15)
# slope parameters
sl     <- round(runif(15,0.5,1.5),2)
la     <- round(runif(15,0,0.25),2)
ua     <- round(runif(15,0.8,1),2)


awm <- PP::sim_4pl(beta = diffpar, alpha = sl,
                   lowerA = la, upperA = ua,
                   theta = rnorm(200))

awm <- as.data.frame(awm)
```

### Estimating and using person parameters 

```{r data_wrangling1}
out <- PPass(respdf = awm,thres = diffpar,
             items="all", mod=c("1PL"), 
             fitindices=c("lz","lzstar","infit","outfit"))

# create a data.table
outdt <- data.table(out)

outdt[, ID := 1:.N]
outdt[, roundest := factor(round(estimate,8))]

# Compute Percentile Ranks with the Person Parameters

outdtu <- unique(outdt[,su := .N, keyby=roundest], by="roundest")
outdtu[,PR :=cumsum(su)/sum(su) * 100]

outdt <- outdt[outdtu[,list(roundest,PR)],,on="roundest"]
setorder(outdt,ID)
outdt[, c("su") := NULL]

# done
outdt
```


### Using person fit statistics 







## Second example


Now there are two groups.

```{r simulate_data2}

awm <- PP::sim_4pl(beta = diffpar, alpha = sl, lowerA = la, 
                   upperA = ua, theta = c(rnorm(500),rnorm(500,0.5,1.2)))

awm <- as.data.frame(awm)


```

### Estimating and using person parameters 

```{r data_wrangling2}
out <- PPass(respdf = awm, thres = diffpar, 
             items="all", mod=c("1PL"), 
             fitindices= c("lz","lzstar","infit","outfit"))


outdt <- data.table(out)

outdt[, ID := 1:.N]
outdt[, agegroup := rep(c("young","old"),each=500)]
outdt[, roundest := factor(round(estimate,8))]

outdtu <- unique(outdt[,su := .N, keyby=c("agegroup","roundest")], by=c("agegroup","roundest"))[,PR :=cumsum(su)/sum(su) * 100, by=agegroup]

outdt <- outdt[outdtu[,list(agegroup,roundest,PR)],,on=c("agegroup","roundest")]

setorder(outdt,ID)
outdt[, c("su") := NULL]
outdt
```