Skip to main content
Smart Learning Environments

Table 3 CTT statistical measures desired values

From: Evaluating the quality of the ontology-based auto-generated questions

CTT statistical measures

Desired values

Literature

Difficulty index average

[0.30-0.90]

(Doran 1980; Ding et al. 2006)

Discrimination index average

≥0.30

(Doran 1980; Zhang and Lidbury 2013)

Point biserial coefficient average

≥0.20

(Ding and Beichner 2009; Zhang and Lidbury 2013; Kline 1986; Ding et al. 2006)

Cronbach’s α

≥0.70

(Doran 1980; Kline 2013a)

Fergusons δ

≥0.90

(Kline 1986; 2013a; 2013b)

Back to article page