# Question

Refer to Exercise 12.35. Fit a single model to the data that relates y to x and x2 with separate coefficients for each of the three crops.

a. Does there appear to be a difference in slopes for the three crops?

b. Does there appear to be a difference in intercepts for the three crops?

c. Does a quadratic model appear to provide and adequate fit the data?

In exercise

a. Does there appear to be a difference in slopes for the three crops?

b. Does there appear to be a difference in intercepts for the three crops?

c. Does a quadratic model appear to provide and adequate fit the data?

In exercise

## Answer to relevant Questions

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