A windmill is used to generate direct current. Data are

Chapter 7, Problem 9E

(choose chapter or problem)

A windmill is used to generate direct current. Data are collected on 45 different days to determine the relationship between wind speed in mi/h \((x)\) and current in kA \((y)\). The data are presented in the following table.

a. Compute the least-squares line for predicting y from x. Make a plot of residuals versus fitted values.

b. Compute the least-squares line for predicting y from ln x. Make a plot of residuals versus fitted values.

c. Compute the least-squares line for predicting ln y from x. Make a plot of residuals versus fitted values.

d. Compute the least-squares line for predicting \(\sqrt {y}\) from x. Make a plot of residuals versus fitted values.

e. Which of the four models (a) through (d) fits best? Explain.

f. For the model that fits best, plot the residuals versus the order in which the observations were made. Do the residuals seem to vary with time?

g. Using the best model, predict the current when wind speed is 5.0 mi/h.

Equation Transcription:

Text Transcription:

(x)

(y)

sqrt{y}