H0: The mean for the first city is the same as the mean for the second city. What are the hypotheses for each comparison? Base your conclusion on the Bonferroni-corrected level of significance. Summarize your findings in a table that reports the t-values, p-values, and conclusions. Carry out two-sample t-tests for all three pairs. Report all three sample means. Also, state which two means are closest to each other.īased on the table below, the means for City A and City B are the closest.Ĭ. Assuming the overall level of significance is 0.05, what is the Bonferroni-corrected level of significance for three groups?ī. Which groups have sample means that are significantly different, and how do they differ?Īns: PreAlg students spend less time doing homework than the others.Ī. Write a clear conclusion based on what you found. PreAlg and InterAlg: 3.64 (t-value), 0.003 (p-value), different (conclusion)ĮlemAlg and InterAlg: 1.49 (t-value), 0.163 (p-value), not different (conclusion) PreAlg and ElemAlg: 5.08 (t-value), 0.000 (p-value), different (conclusion) For a significant difference, the p-value must be less than the Bonferroni-corrected value for the significance level.

For all tests, the null hypothesis is that the two population means are the same, and the alternative hypothesis is that the two population means are different. We have assumed that the conditions for two-sample t-tests are met. The corrected significance level is 0.0167. Fill out the table, reporting all the sample means and standard deviations.įinish the list of all three possible comparisons.įind the corrected value for the significance level by dividing 0.05 by the number of comparisons.

Sigmaplot 11 do not test bonferroni