Chapter 4. Sensation and Perception

Topic: Finding the best way to describe experimental data

Statistical concepts covered:

Introduction

When we talk about sensation and perception, psychophysics plays a central role. Not only do we have to have accurate and reliable ways to measure stimuli and physical responses, but we must also be able to describe the results clearly and concisely. Unfortunately, there is not a one-size-fits-all solution when it comes to describing data. While you might think that talking about the average value of a data set is a reasonable approach (and often it is), the truth is that you must understand the shape of your data distribution and the point that you want to convey before you can decide on the best way to represent your data.

In this exercise, you will investigate several different data distributions and think about possible ways to describe the data. It will be helpful to you to review the text’s coverage of graphic representations and descriptive statistics (specifically mean, mode and median). Sometimes the mean value will be a fair and unbiased model of the data, but other times, the mean may misrepresent the data or even be completely uninformative. As you analyze these data and answer the related questions, you should begin to get a feel for how to select the most accurate methods for describing your findings.