Xcode 3 Unleashed

Chapter 2. Simple Workflow and Passive Debugging

<feature><title>In This Chapter</title>

• Linear Regression: An Example Problem

• Creating a Command-Line Tool

• Dealing with Build Errors

• Simple Debugging

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For most of this book, we work on applications that do linear regression, a simple but informative statistic. Suppose that you have a series of data pairs, such as the quarterly sales figures for a particular department, as shown in Table 2.1.

Table 2.1. Quarterly Sales Figures for a Hypothetical Company (millions of dollars)

Quarter	Sales
1	107.5
2	110.3
3	114.5
4	116.0
5	119.3
6	122.4

A regression line is the straight line that passes nearest all the data points (see Figure 2.1). The formula for such a line is y = mx + b, or the sales (y) for a given quarter ...