Before we begin *Nonlinear Models*, let’s see how the new ideas in this module relate to what we learned in the previous modules, *Types of Statistical Studies and Producing Data*, *Summarizing Data Graphically and Numerically*, and *Examining Relationships: Quantitative Data*.

Recall the Big Picture:

We begin a statistical investigation with a research question. The investigation proceeds with the following steps:

- Produce Data: Determine what to measure, then collect the data.
**← Types of Statistical Studies and Producing Data** - Explore the Data: Analyze and summarize the data.
**←**Summarizing Data Graphically and Numerically, Examining Relationships: Quantitative Data,**Nonlinear Models** - Draw a Conclusion: Use the data, probability and statistical inference to draw a conclusion about the population.

*Types of Statistical Studies and Producing Data* focused on methods for collecting reliable data. *Summarizing Data Graphically and Numerically* focused on summarizing and analyzing data for a quantitative variable. *Examining Relationships: Quantitative Data* focused on linear relationships between two quantitative variables. In *Nonlinear Models*, we focus on nonlinear relationships between two quantitative variables. In the Big Picture of Statistics, the material in this module is still part of exploratory data analysis.