Standard Deviation vs. Standard Error n = sample size Sigma (σ) = standard deviation SEM = standard error of the mean login to view 3 more bullets z-scores login to view 3 more bullets Confidence Interval (CI) Describes the range in which the mean would be expected to fall if the study were performed again and again login to view 3 more bullets Outcomes login to view 2 more bullets T-test vs. ANOVA vs. χ2 T-test login to view 1 more bullet ANOVA (analysis of variance) login to view 1 more bullet χ2 ("chi-squared") login to view 3 more bullets Correlation Coefficient (r) Pearson coefficient, r, is always between -1 and +1 Absolute value indicates strength of correlation between 2 variables Coefficient of determination = r2 Attributable Risk (AR) AR is incidence in the exposed (Ie) - incidence in the unexposed (Iu) = Ie - Iu login to view 3 more bullets The AR percent (ARP) is the attributable risk divided by incidence in the exposed (Ie) login to view 4 more bullets