Chapter 15, Problem 6PS

A production manager wishes to examine the relationship between unit production (number of units produced) and associated costs (total cost). The file CostEstimation contains data for 10 months of production.

a. Construct a scatter plot for unit production and total cost.

b. Fit a quadratic regression model to predict total cost and state the quadratic regression equation.

c. Predict the mean total cost when production is 145 units.

d. Perform a residual analysis on the results and determine whether the regression model is valid.

e. At the 0.05 level of significance, is there a significant quadratic relationship between monthly unit production and total cost?

f. What is the p-value in (e)? Interpret its marring.

g. At the 0.05 level of significance, determine whether the quadratic model is a better fit than the linear model.

h. What is the p-value in (g)? Interpret its meaning.

i. Interpret the meaning of the coefficient of multiple determination.

j. Compute the adjusted $r^2.$

k. What conclusions can you reach concerning the relationship between cost and unit production?