Microsoft Office Tutorials and References

In Depth Information

Fig. 6.30
Worksheet Data for Chapter 6: Practice Problem #1

The resulting printout should contain only the summary output of the regression

analysis on a separate page.

Finally, click on any empty cell on the spreadsheet to “deselect” the regression

table.

6.9 End-Of-Chapter Practice Problems

1. Suppose that you wanted to study the relationship between the number of growth

rings and the age of a Ponderosa pine tree (
Pinus ponderosa
). Is there a

relationship between these two variables? Let’s assume that you can measure

the growth rings that correspond to the number of years the tree has been

growing.

You have decided to use the age of the trees (in years) as the predictor, X, and the

number of growth rings as the criterion, Y. To test your Excel skills, you have

randomly chosen eight trees, and have recorded the hypothetical scores on these

variables in Fig.
6.30
:

Create an Excel spreadsheet and enter the data
using AGE as the independent

variable (predictor) and NUMBER OF GROWTH RINGS as the dependent

variable (criterion).

Important note:

When you are trying to ﬁnd a correlation between two variables, it is important

that you place the predictor, X, ON THE LEFT COLUMN in your Excel

spreadsheet, and the criterion, Y, IMMEDIATELY TO THE RIGHT OF THE X

COLUMN. You should do this every time that you want to use Excel to ﬁnd a

correlation between two variables to check your thinking so that you do not

confuse these two variables with one another.

(a) Create the table using Excel, and then use Excel’s

correl function to ﬁnd

the correlation between these two variables, and round off the result to two

decimal places. Label the correlation and place it beneath the table.

¼

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