Introduction

While medical researchers might be interested in knowing the answers to questions such as ‘Is age related to blood pressure?’ engineers might be interested in knowing the answers to questions such as ‘Is the shear strength of a weld related to its diameter?’ or ‘Is the rate of wear of a petrol engine related to its operating temperature?’ As you already know (from reading the introduction to Section 43.1 concerning the topic of regression), statisticians measure the strength of a relationship between two variables by using a quantity called the correlation coefficient. As you might expect, tests exist which allow us to interpret the meaning of a calculated correlation coefficient.

Prerequisites

Learning Outcomes