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Old 08-07-2012
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Stats Accuracy versus Precision

A scientist tests a medical laboratory's measurement protocol by dividing a single blood sample with a known amount of cholesterol (185 mg/dL) into four equal parts and then submitting each of them for testing as four separate samples. Test results (in mg/dL) from the laboratory are as follows:
Sample 1 204
Sample 2 205
Sample 3 204
Sample 4 203
What can be concluded about the precision and accuracy of the four test measurements?

a) Accurate and precise
b) Accurate but not precise
c) Neither accurate nor precise
d) Precise but not accurate
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Old 08-07-2012
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d) Precise but not accurate.
Precise 'cause the results are practically the same in the four samples, not accurate 'cause they differ from 185.
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May be Precise but not accurate


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It's precise but not accurate. Remember you have 4 terms used for the same thing ( precise, reliable, reproducible, and consistent).
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Old 08-07-2012
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d is correct
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d looks like rx
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d) Precise but not accurate[/QUOTE]
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Old 08-08-2012
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Default correct answer :)

The answer is d) Precise but not accurate

These results are precise because individual results are all similar to each other. Precision is the ability of a measurement to give the same or very similar results with repeat measurements. However, these results are not accurate because they are consistently higher than the true value. Accuracy is present when results approximate those of the phenomenon under study.
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