28. Appendix B Data Set: Weights of Coke Refer to Data Set 12 in Appendix B and test the claim that because they contain the same amount of cola, the weights of cans of regular Coke have the same mean as the weights of Diet Coke. If there is a difference in the mean weights, identify the most likely explanation for that difference.

Pooling. In Exercises 29–32, assume that the two samples are independent simple random samples selected from normally distributed populations. Also assume that the population standard deviations are equal ( ) so that the standard error of the differences between means is obtained by pooling the sample variances.