The interval for the Eastern minus Central comparison is 0.068 to 0.868. Hold the pointer over the points on the graph to view the middle, upper, and lower estimates. Western shipping center mean minus Eastern shipping center mean.Western shipping center mean minus Central shipping center mean.Eastern shipping center mean minus Central shipping center mean.The Tukey confidence intervals show the following pairwise comparisons: The Tukey 95% confidence interval plot is the best graph to use to determine the likely ranges for the differences and to assess the practical significance of those differences. Because each shipping center is in a different group, all shipping centers have average delivery times that are significantly different from each other. The results of the Tukey's test are included in the grouping information table, which highlights the significant and non-significant comparisons. With an α of 0.05, the p-value (0.000) in the Analysis of Variance table provides enough evidence to conclude that the average delivery times for at least two of the shipping centers are significantly different. If the p-value is greater than α, then you fail to reject the null hypothesis and cannot claim support for the alternative hypothesis.If the p-value is less than or equal to a predetermined significance level (denoted by α or alpha), then you reject the null hypothesis and claim support for the alternative hypothesis.The decision-making process for a hypothesis test is based on the p-value, which indicates the probability of falsely rejecting the null hypothesis when it is really true. For this one-way ANOVA, delivery days is the response, and shipping center is the factor. You also perform a Tukey’s multiple comparison test to see which shipping center means are different. To verify this, you perform a one-way ANOVA, which tests the equality of two or more means. Given the graphical analysis in the previous chapter and the descriptive analysis above, you suspect that the difference in the average number of delivery days across shipping centers is statistically significant. The alternative hypothesis is what you believe might be true. The null hypothesis is the initial claim and is often specified based on previous research or common knowledge. Hypothesis tests include two hypotheses (claims), the null hypothesis (H 0) and the alternative hypothesis (H 1). Usually, when you perform a hypothesis test, you assume an initial claim to be true, and then test this claim using sample data. Minitab offers many hypothesis tests, including t-tests and ANOVA (analysis of variance). One of the most common methods used in statistical analysis is hypothesis testing.