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Sample Test

Question 1 of 8

Question 1. A depression rating scale A gives a score of 10, 12, 14, 11 and 12 when used in the same patient by different raters. A different scale B gave comparable values of 20, 7, 6, 23, and 14. When a gold standard test is used, the depression score was equivalent to 12. Choose one right statement from the below:

A. Scale A is very precise but not accurate
B. Scale B is accurate but not precise
C. Scale B is both precise and accurate
D. Scale A is both precise and accurate
E. Scale A and B are both accurate but not precise

Correct Answer is - D. Scale A is both precise and accurate

Description :

Precision is the degree to which a calculated central value (e.g. mean) varies with repeated sampling. The narrower the variation, the more precise the value is said to be.
Factors reducing precision includes 1. Having wider limits of the interval (range) 2. Expecting higher confidence interval (e.g. 99.7% versus 95%). Accuracy refers to the correctness of the mean value – i.e. how close is it to the true population value. Precision is comparable to reliability while accuracy is comparable to validity.

Ref:
http://www.engr.mun.ca/~cdaley/1000/measurem.htm