getTNR {Qval}

Calculate true negative rate (TNR)

Description

Calculate true negative rate (TNR)

Usage

getTNR(Q.true, Q.orig, Q.sug)

Arguments

Q.true

The true Q-matrix.

Q.orig

The Q-matrix need to be validated.

Q.sug

The Q-matrix that has being validated.

Details

TNR is defined as the proportion of correct elements which are correctly retained:

TNR = \frac{\sum_{i=1}^{I}\sum_{k=1}^{K}I(q_{ik}^{t} = q_{ik}^{s} | q_{ik}^{t} \neq q_{ik}^{o})} {\sum_{i=1}^{I}\sum_{k=1}^{K}I(q_{ik}^{t} \neq q_{ik}^{o})}

where q_{ik}^{t} denotes the kth attribute of item i in the true Q-matrix (Q.true), q_{ik}^{o} denotes kth attribute of item i in the original Q-matrix(Q.orig), q_{ik}^{s} denotes kth attribute of item i in the suggested Q-matrix(Q.sug), and I(\cdot) is the indicator function.

Value

A numeric (TNR index).

Examples

library(Qval)

set.seed(123)

example.Q1 <- sim.Q(5, 30)
example.Q2 <- sim.MQ(example.Q1, 0.1)
example.Q3 <- sim.MQ(example.Q1, 0.05)
TNR <- getTNR(example.Q1, example.Q2, example.Q3)

print(TNR)