The graph below shows the results for a participant when discriminating whether a line is greater than 5 inches.
-The lower difference threshold is:
A) 4.75 inches
B) 4.90 inches
C) 5.00 inches
D) 5.05 inches

Question

The graph below shows the results for a participant when discriminating whether a line is greater than 5 inches. 
-The lower difference threshold is:
A) 4.75 inches 
B) 4.90 inches 
C) 5.00 inches 
D) 5.05 inches

Quizplus · Accepted Answer

The lower difference threshold is the smallest difference between two lines that the participant can reliably discriminate. In this graph, the point where the curve intersects the horizontal line at 50% (chance level) is at approximately 4.90 inches. This means that any line difference smaller than 4.90 inches would not be reliably detected by the participant, making 4.90 inches the lower difference threshold.

The Graph Below Shows the Results for a Participant When