Table 3

Illustration of consequences of students’ decisions regarding how they deal with a question for which they do not know the correct answer

Knowledge of Correct Answer (%)
Student DecisionConfidence Scoring Formula60%70%80%90%
Random guessing δ=3apD=0 pR=0b7077.58592.5
Random guessing δ=3,a no questions unansweredpD=−1/4 pR=3/862.571.87581.2590.625
pD=−1/3 pR=1/360708090
pD=−1/2 pR=1/45562.2577.588.75
pD=−1 pR=040557085
Random guessing δ=3,a one-quarter of questions for which student does not know correct answer are unansweredpD=−1/4 pR=3/865.62374.21982.81391.406
pD=−1/3 pR=1/363.33372.581.66790.833
pD=−1/2 pR=1/458.7569.06379.37589.688
pD=−1 pR=04558.7572.586.25
Random guessing δ=3,a one-half of questions for which student does not know correct answer are unansweredpD=−1/4 pR=3/868.7576.56384.27592.188
pD=−1/3 pR=1/366.6677583.333091.667
pD=−1/2 pR =1/462.571.87581.2590.625
pD=−1 pR=05062.57587.5
All questions for which student does not know correct answer are unansweredpD=−1/4 pR=3/87581.2587.593.75
pD=−1/3 pR=1/373.3338086.66793.333
pD=−1/2 pR=1/47077.58592.5
pD=−1 pR=060708090
• a δ represents the number of functioning distractors; thus, the student makes final selection of his or her response to question from among the functioning distractors and the correct answer.

• b Corresponds to number-correct scoring.