Learn R Programming

dexter (version 0.8.5)

probability_to_pass: The probability to pass on a reference test given a score on a new booklet

Description

Given response data that form a connected design, compute the probability to pass on the reference set conditional on each score on one or more target tests.

Usage

probability_to_pass(dataSrc, ref_items, pass_fail, design = NULL,
  predicate = NULL, similar_groups = TRUE)

Arguments

dataSrc

Data source: a dexter project db handle or a data.frame with columns: person_id, item_id, item_score and booklet_id

ref_items

vector with id's of items in the reference set, they must all occur in dataSrc

pass_fail

pass-fail score on the reference set

design

A data.frame with columns booklet_id (if multiple booklets) and item_id defining the target test booklet(s), if NULL (default) this will be derived from the dataSrc and the probability to pass will be computed for each test score for each booklet in your data.

predicate

An optional expression to subset data in dataSrc, if NULL all data is used

similar_groups

When TRUE it is assumed that candidates taking the reference test and the target tests are similar in ability. If they are similar, the score distribution on the target test is estimated more precisely. Works only when design contains booklet_id's.

Value

An object of type p2pass. Use coef() to extract the probablity to pass for each booklet and score. Use plot() to plot the probabilities, sensitivity and specificity.

Details

Note that this function is computationally intensive and can take a long time to run, especially when computing the probability to pass for multiple target booklets.

For any possible score k, we use a Gibbs sampler to calculate

where:

\(\theta\)

is student ability

\(b\)

are the item parameters

is the score on the reference test

\(c\)

is an established pass_fail score on the reference test

is the score on the booklet

\(x\)

are the observed data

This probability can be used to establish a pass-fail score for the new booklet.