Unformatted text preview: So based on Table 3.26, we see that for the rule "You are drunk if your total FST is 2 2," the false
positive rate (FPR) is 27/29 = 0.931 (93.1%), and the sensitivity is 266/267 = 0.996 (99.6%).
Different rules have different FPRs and sensitivities. That is, if the rule is "You are drunk if your total FST
is 2 4," the FPR and sensitivity will be different than that we just calculated. A plot of sensitivity (y-axis)
versus FPR (x-axis) for different rules is called a Receiver Operating Characteristic Curve (ROC).
For this assignment, you need to turn in:
1. A completely filled out copy of Table 3.27 below. If you want to receive full credit, you will need
to make sure that all the entries are correct. Take your time on the calculations.
2. An ROC plot of the 10 values of the rule given. This has to be completed with computer plot
software (such as Excel)
3. A decision and defense of what you think the best rule is, based on the information in your
plot. There won't be only one clearly correct answer here, only evidence that you are aware
of performance issues as the rules change.
All three of these pieces need to be placed in a carefully written final paper. Your instructor will give
you the details concerning format, style, and submission procedure.
TABLE 3.27 FPRs and Sensitivities by FST Score
RULE: You are drunk if your total FST
score is greater than or equal to:
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- Fall '12