Microsoft Office Tutorials and References
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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.
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