Green versus yellow using the minitab output in figure 294

Question

Green versus yellow. Using the Minitab output in Figure 29.4, verify the values for the sample contrast  ₂ and its standard error given in Example 29.7. Give a 95% confidence interval for the population contrast L₂. Carry out a test of the hypothesis H₀: L₂= 0 against the two-sided alternative. Be sure to state your conclusions in the setting of the study.

Example 29.7:

Figure 29.4 displays the Minitab ANOVA output for the study on attracting cereal leaf beetles. The pooled estimate of σ  is s_p = 5.672, and the number of degrees of freedom for error is 20. Minitab does not offer contrasts, so we must use a calculator. The three sample contrasts and their standard errors are

                                          

FIGURE 29.4: