Final answer:
Higher d' values on the ROC curve imply a strong distinction between true positives and false positives, with a d' of 0.834 indicating a significant difference in exam scores between two groups of students.
Step-by-step explanation:
Higher values of d' in the ROC (Receiver Operating Characteristic) curve indicate a greater ability to distinguish between signal and noise, meaning that it is easier to differentiate true positives from false positives. In the context of exam scores, a d' of 0.834 is considered large, as it exceeds Cohen's threshold of 0.8 for a large effect size. This signifies a significant difference between the means of the final exam scores of online students and students in a face-to-face class, reflecting the effectiveness of the measurement in separating the two groups.