Regression tutorial analysis

Regression Analysis Tutorial


INTRODUCTION

Regression analysis can be used to identify the line or curve which provides the best fit
through a set of data points. This curve can be useful to identify a trend in the data, whether it is
linear, parabolic, or of some other form. Regression analysis can be performed using different
methods; this tutorial will explore the use of Excel and MATLAB for regression analysis. In
addition to fitting a curve to given data, regression analysis can be used in combination with
statistical techniques to determine the validity of data points within a data set. For example, the
standard deviation for a data set can easily be determined, and any data points existing outside of
the 3 σ range can be reviewed to determine if they are valid points.

REGRESSION ANALYSIS USING EXCEL

Exercise A-1

In Excel, generate a plot of the seven points given in Table 1. If you are unfamiliar with
Excel, detailed instructions on how to do this are given in Appendix A.

Table 1. Data points to be used for Excel examples.
x-value y-value
2 3
45
8 7
117.5
14 8
189
21 12

Exercise A-2

Using all data points in the set, use Excel tools to perform a linear regression on the data. To
do this, select the graph containing the data set, then select:
Chart
Add Trendline
Type
Trend/Regression type → Linear
Options
Select Display equation on chart
Select Display R-squared value on chart
OK
The graph will ...