lab1.pdf - Nguyen Hai Lam V00914037 STAT 256 LAB 1...

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Nguyen Hai Lam V00914037 STAT 256 LAB 1 Instructor: Chi Kou P1. 1. > var.test(men.wt, women.wt) F test to compare two variances data: men.wt and women.wt 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 a. σ1^2 = true population variance of the weight of men σ2^2 = true population variance of the weight of women b. H0: σ1^2 = σ2^2 versus H1: σ1^2 σ2^2 at α = 0.2 c. Test Statistic F = 2.7509 d. p-value = 0 e. Since p-value < 0.2, we reject H0 and use unpooled procedures. 2. > t.test(men.wt, women.wt, alternative = 'greater', var.equal = F) Welch Two Sample t-test data: men.wt and women.wt t = 9.3547, df = 175.53, 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
a. μ 1 = true mean height of men μ 2 = true mean height of women b. H0: μ 1 = μ 2 versus H1: μ 1 μ 2 at α = 0.1 c. Test Statistic t = 9.355 d. p-value = 0 < 0.1 e. There is strong evidence against H0. Since the p-value is less than 0.1, reject H0 at alpha level

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