PSY 252 Lecture Notes - Lecture 3: Power Law, Swedish Krona, Detection Theory
Document Summary
Noise: distribution of internal responses when no tumor is present. More lax on criterion= more hits but more false alarms. Less lax: less hits but less false alarms. Signal detection theory detects sensitivity but also seeks to answer what criteria the test subject is looking for. Signal detection theory is important because it improves on old methods and acts as a loop around bias (slide 2) Increasing d" (d prime) = more sensitive d"=1 (lots of overlap) d"=3 (not much overlap) D" is trying to capture how much overlap there is between noise and signal (slide 3) Both individuals have the same hit rate, but ss1 has more false alarms. To know how sensitive these subjects are lets calculate their d prime d"= z score (hits)- z score (false alarms) d"= z(h)- z(fa) How much must the stimulus change before you notice the changes (slide 3) Method of constant stimuli to establish the difference threshold (dt) for heaviness.
