Comparing the Lifetimes of two Brands of Batteries

Abstract

In this paper, we report a case study that illustrates the importance in interpreting the results from statistical tests, and shows the difference between practical importance and statistical significance. This case study presents three sets of data concerning the performance of two brands of batteries. The data are easy to describe and understand, familiar to students, and allow a range of analyses, from simple to more complex. The data were the basis of a claim made in an advertisement, and this claim is re-assessed using the data to show that the company undersold the performance of their batteries from a statistical point-of-view in one of the three tests. However, a challenge is how such a conclusion can be communicated to the public succinctly but correctly.

• Real data
• t-tests
• Hypothesis tests
• Experimental design
• Practical significance