STATS 401 Study Guide - Midterm Guide: Test Statistic, Null Hypothesis, Scatter Plot
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Each response is worth 5 points, a perfect score is 60 points. Show your work: two bivariate samples of sample size 50 are displayed as scatterplots on the next page. For each of the scatterplots, one row of the following table gives the correct values of (regression intercept), (regression slope), (regression error estimate), and r (sample correlation coe cient). We observe a bivariate data set and intend to carry out an analysis using the correlation coe cient. For parts a and b below, we are interested in testing the null hypothesis. P (r > 0. 25) = p (r > 0. 255) Solution: let c be the unknown value on the correlation scale, and let c be its. To nd c, log((1 + c)/(1 c))/2 = 0. 32. Solution: r = 0. 87, so the ci on the r scale is 0. 87 1. 96/ Mapping back to the r scale gives (0. 52, 0. 82).
