The statement "factory overhead is a function of machine hours with coefficient of determinationr ) = 70 percent" is correctly interpreted as
a. 70 percent of total variation of factory overhead is explained by the regression equation or the change in machine hours while the remaining 30 percent is accounted for by something other than machine hours.
b. An r-squared of 0.70 with a regression equation means that predictions will be accurate 70% of the time.
c. 30 percent of total variation of factory overhead is explained by the regression or the change in machine hours while 70 percent is accounted for by something other than machine hours.
d. 30 percent of overhead cost prediction might show results outside confidence interval determined by the dard deviation