# The paper Commercially Available Plant Growth Regulators and Promoters Modify Bulk Tissue Abscisic Acid Concentrations in Spring

## Question:

a. Construct a scatterplot of y = soil moisture deficit versus x = days after sowing. Does the relationship between these two variables appear to be linear or nonlinear?

b. Fit a least-squares line to the given data and construct a residual plot. Does the residual plot support your conclusion in Part (a)? Explain.

c. Consider transforming the data by leaving y unchanged and using either

Which of these transformations would you recommend? Justify your choice using appropriate graphical displays.

d. Using the transformation you recommend in Part (c), find the equation of the least-squares line that describes the relationship between y and the transformed x. y^ = 166.490 - 6109.479 1/x 2

e. What would you predict for soil moisture deficit 50 days after sowing? For 100 days after sowing?

f. Explain why it would not be reasonable to predict soil moisture deficit 200 days after sowing.

## Step by Step Answer:

**Related Book For**

## Statistics The Exploration & Analysis Of Data

**ISBN:** 9780840058010

7th Edition

**Authors:** Roxy Peck, Jay L. Devore