Preliminary
Analysis of Data

Introduction

When you gather data in lab you typically are trying to explain the relationship between a particular response and one or more factors. For example, you might be interested in how the concentration of lead in soil (the response) varies as a function of the soil's distance from a highway (the factor). After collecting samples from different locations and completing the analysis you have a data set consisting of lead concentrations and distances from the highway.

How might you begin to analyze your data. Two common approaches are to examine the data visually, looking for interesting relationships between the response and the factors, and to summarize quantitatively the data.

After you complete this module you should:

- understand the difference between a population and a sample
- appreciate the importance of visually examining your data
- be able to summarize your data quantitatively

To work through this module we need a question to investigate, which for us will be:

What is the mass of a US penny in circulation?

Your goal is to report the best estimate for a US penny’s mass, as well as a sense of the variability in that mass. Begin with Problem 1.