Test and CI for Two Variances: machine 1, machine2 Method 0: standard deviation of machine 1 02: standard deviation of machine2 Ratio: 01/02 The Bonett and Levene's methods are valid for any continuous distribution. Descriptive Statistics Variable N StDev Variance 95% CI for machine 1 20 2.278 machine2 20 7.581 5.190 57.466 (1.769, 3.252) (5.988, 10.639) 95% CI for Ratio Ratio of Standard Deviations Estimated 95% CI for Ratio Ratio 0.300512 using Bonett (0.195, 0.455) using Levene (0.163, 0.457) Test and CI for Two Variances: machine 1, machine2 Test Null hypothesis Ho: 01/0 = 1 Alternative hypothesis H: 01/02 1 Significance level = 0.05 Test Method Statistic DF1 DF2 P-Value Bonett Levene 19.28 1 0.000 20.93 1 38 0.000 Bonett Levene machine 1 machine2 Test and CI for Two Variances: machine 1, machine2 Ratio = 1 vs Ratio * 1 95% CI for (machine 1) / (machine 2) 0.2 0.4 0.5 95% CI for 0.8 1.0 " 10 Bonett's Test P-Value 0.000 Levene's Test P-Value 0.000 Method Bonett Test Statistic DF1 DF2 P-Value Levene 19.28 20.93 1 0.000 1 38 0.000 Bonett Levene machine 1 machine2 machine 1 machine2 Test and CI for Two Variances: machine 1, machine2 Ratio = 1 vs Ratio * 1 95% CI for (machine 1) / (machine 2) 0.2 0.4 0.5 95% CI for 0.B 1.0 Boxplot of machine 1, machine 2 10 90 95 100 105 110 115 Bonett's Test P-Value 0.000 Levene's Test P-Value 0.000