STAT255.pdf - Last Name First Name V00 Stat 256 Lab 1...

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Last Name, First Name V00###### Stat 256 Lab 1 Instructor: C. Barone Problem 1 Code and Output: > var.test(m.weight,w.weight) F test to compare two variances data: m.weight and w.weight F = 2.7509, num df = 111, denom df = 132, p-value = 3.488e-08 alternative hypothesis: true ratio of variances is not equal to 1 95 percent confidence interval: 1.927248 3.948812 sample estimates: ratio of variances 2.750934 > t.test(m.weight,w.weight,alternative="greater",var.equal = F) Welch Two Sample t-test data: m.weight and w.weight t = 9.3547, df = 175.528, p-value < 2.2e-16 alternative hypothesis: true difference in means is greater than 0 95 percent confidence interval: 14.53004 Inf sample estimates: mean of x mean of y 81.97321 64.32331 1. (a) Let σ 1 2 , σ 2 2 be the true variance (in kg 2 ) of the men’s weights and women’s weights (respectively). (b) Test H 0 : σ 1 2 2 2 , H 1 : σ 1 2 ≠σ 2 2 at the significance level α= 0.2 (c) The value of the test statistic is 2.7509. (d) The p-value is 3.488e-08 (by which R means 3.488 × 10 8 ) (e) Since the p-value is less than the significance level, we reject the null hypothesis; we conclude that

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