USMLE Step 1 Biostatistics/Epidemiology with complete solution

USMLE Step 1 Biostatistics/Epidemiology with complete solution Sensitivity - answerTP / (TP + FN) Specificity - answerTN / (TN + TP) Positive Predictive Value - answerTP / (TP + FP) Negative Predictive Value - answerTN / (FN + TN) Incidence Rate - answer# of new cases in a certain time period / population that is at risk during that time period This looks at new incidences occurring during a time period Prevalence - answer# of existing cases / population at risk Looks at ALL current cases Odds Ratio - answer(a/c) / (b/d) OR ad / bc Relative Risk - answer[a / (a + b)] / [c / (c + d)] Attributable Risk - answer(a / (a+b) ) - (c / (c+d) ) Gaussian curve standard deviation %'s - answer+/- 1 SD = 68% +/- 2 SD = 95% +/- 3 SD = 99.7% Type 1 error (alpha) - answeryou sAw a difference that did not really exist (convicting an innocent man) Type 2 error (beta) - answeryou were Blind to a difference that did exist