Consider the regression model fit to the nisin extraction data in Exercise 12-14. Use nisin extraction as the response.

a) Test for significance of regression using = 0.05. What is the p-value for this test?

b) Construct a t-test on each regression coefficient. What conclusions can you draw about the variables in this model? Use = 0.05.

c) Comment on the effect of a small sample size to the tests in the previous parts.

d) Calculate 95% confidence intervals on each regression coefficient.

e) Calculate a 95% confidence interval on mean nisin extraction when x1=15.5 and x2=16.

f) Calculate a prediction interval on nisin extraction for the same values of the regressors use in the previous part.

g) Comment on the effect of a small sample size to the widths of these intervals.

x1	x2	y
13	11	62.8739
15	11	76.1328
13	13	87.4667
15	13	102.3236
14	12	76.1872
14	12	77.5287
14	12	76.7824
14	12	77.4381
14	12	78.7417

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