Biotin Intake in Chicks Groups of 10- day-old chicks were randomly assigned to seven...

Biotin Intake in Chicks Groups of 10- day-old chicks were randomly assigned to seven treatment groups in which a basal diet was supplemented with 0, 50, 100, 150, 200, 250, or 300 micrograms/kilogram (µg/kg) of biotin. The table gives the average biotin intake (x) in micrograms per day and the average weight gain (y) in grams per day.

In the MINITAB printout, the second-order polynomial model

is fitted to the data. Use the printout to answer the questions.

a. What is the fitted least-squares line?

b. Find and interpret its value.

c. Do the data provide sufficient evidence to conclude that the model contributes significant information for predicting y?

d. Find the results of the test of . Is there sufficient evidence to indicate that the quadratic model provides a better fit to the data than a simple linear model does?

e. Do the residual plots indicate that any of the regression assumptions have been violated? Explain.