Published online by Cambridge University Press: 01 January 2025
A description is given of a diagram (available separately) for computing biserial or point biserial correlation coefficients. The diagram is maximally useful where large numbers of coefficients are to be calculated in test item analysis. The diagram is entered with the mean criterion score of the group passing the item and the proportion of correct answers to the item.
The diagram is published in reduced size for illustrative purposes only. Interested readers may obtain a copy of the diagram, size 101 x 16 inches, without charge by writing to the Test Development Section, United States Civil Service Commission, Washington 25, D. C., requesting a copy of Test Technical Series No.17.