Discussion Question 3: The Correlation Coefficient There are two ways we may calculate the correlation coefficient r (also called Pearson's r) the hard way, calculating each step in the formula, and the easy way, plugging the data into a calculator or computer that has the formula for the correlation coefficient programmed into it. In this Discussion Question, we will compute the correlation between two variables in a data set the hard way as a group. Each person who contributes to the thread will perform one more step toward finding the value of r. But each person will also compute the easy way using a programmable calculator or computer. Here is our scenario: Eight restaurants belonging to the same franchise operate in different cities. The restaurants have different levels of daily sales. You suspect that part of the variation in sales may come from competition with other restaurants. You collect two pieces of data for each restaurant in the franchise, the number of competitors within one mile and the average daily sales of the restaurant. The data are summarized in the table below. Number of Competitors within 1 mile (x) Average daily sales (in thousands) (y) 1 4.0 3.3 2 3.1 3 2.5 3 2.9 2.5 2.8 2.0