STAT 301 Midterm: Standard error, confidence intervals, RR, O, OR, test of homogeneity, test of independence
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Want confidence intervals for these statistics (rr, , or) It is hard to calculate the standard error for these three statistics. Solution: find the standard error of their natural logs. Natural log is denoted ln in math books. So whenever i write log , i mean the natural log. S. e. of log (odds) = n x(n x) x = total successes n = total observations. S. e. of log (rr) = 1 p1 p1 n1. Or n1 x1 n1 x1 n2 x2 n2 x2. S. e. of log (or) = 1 x1. So ci for the log of the statistic is log (stat) zcrit (s. e. ) Ci of log (odds) = log (odds) zcrit . Ci of log (rr) = log (rr) zcrit n1 x1. Ci of log (or) = log (or) zcrit 1 n1 x1 n x(n x) n2 x2 n2 x2. Thus, to get the cis for the statistics, we take e to the power of the ci of.
