Unformatted text preview: Assumptions include random sampling of and independence among plants. (b) Observations are clearly paired: each leaf observa tion is paired to the root observation made on the same plant. Therefore, one would use a twosided pairedsample ttest, provided that the distribution of difference (leaf expression root expression) is not too far from a normal distribution. Note: there is no need to assume that σ 1 = σ 2 and no need to assume normality of gene expression. Only the normality of the expression difference is needed. 5(a) false : we mostly use a tdistribution. The normal distribution is only used when the variance is known. true true because zquantiles are smaller than tquantiles. false : the confidence interval is centered at the sam ple mean (¯ y , which is random) while the notrejection region is centered at the null hypothesis μ (not ran dom  known before collecting the data) true true : they both have the same length, which is twice z α/ 2 * σ/ √ n . Summary of grades: Frequency 20 40 60 80 100 10 20 30 40 ● ● ● ● ● ● ● 76 83 89 1...
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 Fall '08
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 Statistics, Binomial, Normal Distribution, Variance, 2sided test

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