Question

Stat 210 Quiz 6: The Minitab output for the packing time example is as follows: Two-Sample T-Test and CI: New machine, Old machine Two-sample for New machine vs old machine Mean St Dev SE Mean 42.140 0.683 0.22 43.230 0.750 0.24 10 10 New machine old machine (old machine) Difference = u(New machine) - Estimate for difference: -1.090 18 -value = -3.40 P-Value - 0.003 DY 1 st OE CELOzence (VSP Both use pooled St Dev=0.7174 - Test the variances of this test.

Answer 1

Using Minitab, (Stat -> Basic Statistics -> 2 variances), we get the following output -

Minitab - Untitled - [Session] O File Edit Data Calc Stat Graph Editor Tools Window Help Assistant XATO 11-11-2019 12:36:40 Welcome to Minitab, press F1 for help. Test and Cl for Two Variances Method Null hypothesis Alternative hypothesis Significance level o(First) / (First) / a = 0.05 (Second) = 1 (Second) # 1 F method was used. This method is accurate for normal data only. Statistics Sample First Second N 10 10 StDev Variance 0.683 0.466 0.750 0.563 95% CI for St Devs (0.470, 1.247) (0.516, 1.369) Ratio of standard deviations = 0.911 Ratio of variances = 0.829 95% confidence Intervals CI for Variance Ratio (0.206, 3.339) CI for StDev Ratio (0.454, 1.827) Method Tests Test Method DF1 DF2 Statistic P-value 0.83 0.785 MTB >

Since P-value = 0.785 > 0.05, so at 5% level of significance,we can conclude that the two variances are not significantly different.