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Unformatted text preview: mal. There are statistical methods to test for normality but we don’t cover those tests in this course. We can use the methods discussed in 1181. Plot the histogram (or normal probability plot) if we see a bell shaped (or close to a straight line on a normal probability plot), then the normality requirement is fulfilled. Slide 25 s Example : Solution • The problem objective is to describe the population average of annual returns from buying shares of quality awardwinners. • Solving by hand (assume the data set is provided), we can get x = 15.02 s 2 = 68.98 s = 68.98 = 8.31
x ± tα 2, n −1 s 8.31 = 15.02 ± 2.064 = [11.59,18.45] n 25
t.025,24 • We have 95% confidence that the population average annual return is in between 11.59 and 18.45 (in million$) Slide 26 Interval Estimation of a Population Proportion
s s When the population consists of nominal data, the only inference we can make is about the proportion of occurrence of a certain value. The parameter π was used before to calculate these...
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- Spring '09