Task 2 - SDT Flashcards
Noise can be qualified in two main sources…
External and Internal
What does a Correct Rejection entail?
A correct maintenance of the hypothesis that there is no signal among the noise.
In what way does the signal strength relative to the noise impact the density function?
It shifts is horizontally.
What is the criterion in SDT?
The cu-off value on X, where the decision is made, whether a signal is present or not.
The discriminability Index d’ is the ratio of…
The difference between the means and the standard deviation
What is plotted on a ROC Graph?
X-Axis: False Alarm Rate
Y-Axis: Hit Rate
When is the ROC curve less bent upwards?
When the signal is weak, so less optimal criterions can be established.
What does the objectively optimal beta depend on?
The probability of a signal occurring.
How does the subjectively optimal beta differ from the objective version?
It takes into account the cost-benefit ratios.
Beta should be smaller, if subjectively …
Misses are costly
If hits are worth more than misses are costly, the criterion should be:
Liberal
What do people usually react more quickly to when adjusting their beta value: Changing signal probabilities or changing payoff ratios?
Payoff ratios
What exactly does the ROC curve show?
The line where sensitivity is constant across changing levels of bias.
How is Beta represented in ROC curves?
It is the ratio of the X and Y corrdinates.
When a person answers every item using the flip of a coin, how would the corresponding ROC curve look?
It would be a straight line with a slope of 1.
