23. The least squares method is based upon:

a. Minimizing the unexplained variation.

b. Maximizing the unexplained variation.

c. Minimizing the explained variation.

d. Maximizing the total variation.

24. Given a regression cost function, y = 20 + 4x with a standard error of $6.80, and x represents the activity of direct labor hours, what is the estimated cost when x = 15?

1. $15.60 c. $160.00
2. $31.20 d. $ 80.00

25. Refer to the preceding question. What is the 95% prediction interval, using the non-precise guidelines discussed in the lecture, for the true cost when the number of direct labor hours is 15?

1. $66.40 < the true cost < $93.60
2. $93.60 < the true cost <$66.40
3. $47.20 < the true cost < $93.60
4. Cannot be determined from the given information.