Microsoft Office Tutorials and References

In Depth Information

**Exponential Regression Used to Predict Future Generations**

Exponential Regression Used to Predict Future Generations

It would be interesting to run an exponential regression and see the prediction

for future generations but also for the known generations. This would enable

you to see how well the prediction tracks with current values. To do this,

follow these steps:

11. Add new generation numbers in A12:A19. The GROWTH function uses

these numbers and returns an array of values.

22. Select the entire range C2:C19 for the results before entering the for-

mula.

33. Put the known_y'sin B2:B11. The known_x'sare in A2:A11. Put the

new_x'sin A2:A19. The formula is =GROWTH(B2:B11,A2:A11,A2:A19).

44. After typing the formula, hold down Ctrl+Shift while pressing Enter.

This should cause the formula to return values in each cell in

C2:C19.

55. To visualize the original data and the prediction, plot A1:C19 on a line

chart. Numbers at the end of the progression (24 million) make the

scale of the chart so large that you cannot see the detail of the first

12 generations.

66. Right-click the numbers along the y-axis and select Format Axis. On

the Scale tab, select Logarithmic Scale. The resulting chart enables

you to examine both the smaller and larger numbers in the chart.

Using

Using
PEARSON

to Determine Whether a Linear Relationship Exists

Remember that Excel blindly fits a regression line to any data set. The fact

that Excel returns a regression line does not mean that you should use it to

make any predictions. The initial question to ask yourself is,
“
Does a lin-

ear relationship exist in this data?
”

PEARSON
to Determine Whether a Linear Relationship Exists