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Fingerprint expertise. Contrary to what is presented on TV
Chapter 3, Problem 81E(choose chapter or problem)
Problem 81E
Fingerprint expertise. Contrary to what is presented on TV shows like CSI, fingerprint identification is not fully automated. Expert examiners are required to identify the person who left the fingerprint. A study published in Psychological Science (August 2011) tested the accuracy of experts and novices in identifying fingerprints. Participants were presented pairs of fingerprints and asked to judge whether the prints in each pair matched. The pairs were presented under three different conditions: prints from the same individual (match condition), nonmatching but similar prints (similar distracter condition), and nonmatching and very dissimilar prints (nonsimilar distracter condition). The percentages of correct decisions made by the two groups under each of the three conditions are listed in the table.
Condition |
Fingerprint Experts |
Novices |
Match |
92.12% |
74.55% |
Similar Distracter |
99.32% |
44.82% |
Nonsimilar Distracter |
100% |
77.03% |
Source: Based on Tangen, J. M., Thompson, M. B., & McCarthy, D. J. “Identifying fingerprint expertise,” Psychological Science, Vol. 22, No. 8, August 2011 (Figure 1).
a. Given a pair of matched prints, what is the probability that an expert failed to identify the match?
b. Given a pair of matched prints, what is the probability that a novice failed to identify the match?
c. Assume the study included 10 participants, 5 experts and 5 novices. Suppose that a pair of matched prints was presented to a randomly selected study participant and the participant failed to identify the match. Is the participant more likely to be an expert or a novice?
Questions & Answers
QUESTION:
Problem 81E
Fingerprint expertise. Contrary to what is presented on TV shows like CSI, fingerprint identification is not fully automated. Expert examiners are required to identify the person who left the fingerprint. A study published in Psychological Science (August 2011) tested the accuracy of experts and novices in identifying fingerprints. Participants were presented pairs of fingerprints and asked to judge whether the prints in each pair matched. The pairs were presented under three different conditions: prints from the same individual (match condition), nonmatching but similar prints (similar distracter condition), and nonmatching and very dissimilar prints (nonsimilar distracter condition). The percentages of correct decisions made by the two groups under each of the three conditions are listed in the table.
Condition |
Fingerprint Experts |
Novices |
Match |
92.12% |
74.55% |
Similar Distracter |
99.32% |
44.82% |
Nonsimilar Distracter |
100% |
77.03% |
Source: Based on Tangen, J. M., Thompson, M. B., & McCarthy, D. J. “Identifying fingerprint expertise,” Psychological Science, Vol. 22, No. 8, August 2011 (Figure 1).
a. Given a pair of matched prints, what is the probability that an expert failed to identify the match?
b. Given a pair of matched prints, what is the probability that a novice failed to identify the match?
c. Assume the study included 10 participants, 5 experts and 5 novices. Suppose that a pair of matched prints was presented to a randomly selected study participant and the participant failed to identify the match. Is the participant more likely to be an expert or a novice?
ANSWER:
Solution:
Step 1 of 4:
The experiment under consideration is testing the accuracy of experts and novices in identifying the fingerprints.
The data regarding the percentage of decisions made by the two groups under three different conditions is given.
Using this data we have to find the required values.
The given data is
Conditions |
Fingerprint experts |
Novices |
Match |
92.12% |
74.55% |
Similar Distracter |
99.32% |
44.82% |
Non similar Distractor |
100% |
77.03% |