USMLE STEP 3 BIOSTATS EXAM PAPER 2026 COMPLETE QUESTIONS AND ANSWERS GRADED A+

USMLE STEP 3 BIOSTATS EXAM PAPER 2026
COMPLETE QUESTIONS AND ANSWERS
GRADED A+


◉Mean. Answer: average of a group of number


◉Median. Answer: the middle number when arrange in order


◉Mode. Answer: the number that appears most


◉Bell curve. Answer: normal- mean = median = mode
positively skewed- mean > median > mode
negatively skewed- mean < median < mode


◉Accurate. Answer: Equivalent to validity


What the gold standard test is. If something is true it is accurate.


◉Reliability. Answer: Reproducible, doesn't mean accurate (true)

, ◉SEM. Answer: Measure od how tightly grouped a set of data is.


Just know that the smaller the SEM, the more precise the data


◉Z-score. Answer: is how far you are from the mean


◉Confidence interval. Answer: 95 CI is what you are looking for.


When an outcome has CI that cross 1.0 it is not significant.


◉Correlation coefficient (r). Answer: level of connection or
correlation b/n two groups


+1 positive correlation
-1 inverse correlation
0 no correlation


◉T test. Answer: Assess different groups of data b/n two groups
that are not normal or bell shaped.


◉ANOVA. Answer: Assess different groups of data b/n 3 or more
groups that are not normal or bell shaped.