Question

Please use the Buena excel file. The data show different attributes of buses that went through their regular maintenance. The buses are made by three different manufacturers: Bluebird, Keiser, and Thompson. Assuming these are random samples of bus populations, normally distributed, from these manufacturers. Consider Bluebird and Keiser.

a. Use a 0.05 significance level and test whether there is a difference in the mean maintenance costs of the buses from these manufacturers. What is the p-value?

b. Use a 0.01 significance level and test whether there is a difference in the mean mileage (Miles) before the maintenance from these manufacturers. What is the pvalue?

c. Assume that the means of Keiser and Thompson populations are equal. Test whether there is a difference in the mean maintenance costs of the buses from these manufacturers at a 0.01 significance level. What is the p-value?

Answer 1

The question involves using an Independent Samples t-test to compare mean maintenance costs and mean mileage between different bus manufacturers,

Step-by-step explanation:

The question relates to hypothesis testing, where students are required to determine if there is a statistically significant difference in mean maintenance costs and mean mileage between buses from different manufacturers.

An Independent Samples t-test would normally be used for comparing the means of two independent groups when the variances are assumed to be equal and the populations are normally distributed.

As for the maintenance costs of Keiser and Thompson, given the assumption that the population means are equal, a t-test would again be used with a 0.01 significance level to determine if there is a difference in means.

To find the p-value, the student would calculate the t-statistic based on the sample means and standard deviations, then compare this to a t-distribution to find the probability of observing such a difference if the null hypothesis were true.

Decisions on whether to reject the null hypothesis would be based on whether the p-value is less than the chosen significance level.

The exact p-values would need to be calculated using statistical software or critical values from a t-distribution table, since the problem specifics are not provided here.

For drawing conclusions, a p-value below the significance level would lead to rejection of the null hypothesis, indicating a significant difference in means.