Do students that finish exams first obtain better grades? A professor has kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of 19.6, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviation of 24.9.
Is this a significant difference at alpha = .05? Need to:
(a) State the hypotheses for a right-tailed test.
(b) Obtain a test statistic and p-value assuming equal variances.
Interpret these results.
(c) Is the difference in mean scores large enough to be important?
(d) Is it reasonable to assume equal variances?
(e) Carry out a formal test for equal variances at alpha = .05, showing all steps clearly.
Step by step methods for testing the hypothesis under the 5 step approach is discussed here. An Excel template for each problem is also included. This template can be used to obtain the answers of similar problems.