8.3.3. Fit the simple regression mean function again, but this time assume that Var(Lab|Field) = σ^2/ Field. Get the score test for the fit of this variance function. Also test for nonconstant variance as a function of batch; since are arbitrarily numbered, be sure to treat Batch as a factor. (Hint: Both tests are extensions of the methodology outlined in the text. The only when computing the statistic.)