[Excel Problem]

All of the Projects for MAT 114 will require you to utilize several features of a spreadsheet program. This problem is designed to introduce you to such features.

This problem will demonstrate how a spreadsheet program can test the strength of the correlation between values of two variables.

Ecologists are studying a certain species of riparian reed, Arundo donax L., and they collected data by finding examples of the reed along the bank of a river in Southern California and measuring the distance each reed was from the bank and also its diameter. The ecologists believe there is a linear relationship between these quantities. A portion of the data which was collected is provided below.

Distance	Diameter
1.3	4.51
1.4	4.42
1.6	4.41
2.6	4.51
3.8	4.43
8.7	3.74
9.1	4.15
11.4	3.6
12.5	2.99
14.6	2.82
18.2	3
22.3	2.63

a) Which quantity is most likely to be the independent variable? b) Does it appear this appear these quantities are positively related or negatively related? (answer POS if positive, NEG if negative) Next, our goal will be to create a linear regression trendline for this data and to test the strength of the correlation - both of which can be efficiently accomplished in a spreadsheet program.

Open a spreadsheet program (such as Microsoft Excel) and complete the following steps:

1) Select the data above; copy and paste it into the spreadsheet program.

2) Highlight all of the data within the spreadsheet program.

3) Click "Insert" on the menu bar; select/click Scatter plot. (A scatter plot displaying your data should appear.)

4) Right-click on one of the data points in the scatter plot; select "Add Trendline..."

5) Within Trendline Options, select "Linear" and "Display R-squared value on chart"

c) What is the R-squared value for the linear trendline for this data set? d) What is the R value (the correlation coefficient) for the linear trendline for this data?