USMLE-Rx Step 1 Qmax Challenge #1557

Check out today’s Step 1 Qmax Question Challenge.

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A 50-year-old woman presents for a routine physical examination. She has recently retired from her position as a statistics professor. During her visit she complains about a breast lump near her left areola. A breast examination is concerning for a smooth mass near the patient described location. The physician performs a cross sectional study looking at all women aged 50-99 years in his town and determines the prevalence of all breast masses of this age group.

Using the letters in the figure, which of the following equations would help the physician accurately describe the prevalence of breast masses to this statistician?

A. (W + X) / (W + X + Y + Z)
B. (W + Y)/(W + X + Y + Z)
C. W/(W + X + Y + Z)
D. W/(X + Y + Z)
E. W/(X + Z)

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