Figure 23-1
Lee Ltd $\Sigma$ =
Summation
-Refer to Figure 23-1

Figure 23-1
Lee Ltd. manufactures and sells party items. The following representative direct labour hours and production costs are provided for a four-month period: Let
a
=
Fixed production costs per month
b
=
Variable production costs per direct labour hour
n
=
Number of months
X
=
Direct labour hours per month
Y
=
Total monthly production costs
$\Sigma$
=
Summation
-Refer to Figure 23-1. The cost function derived by the least-squares cost estimation method

A) is linear.
B) must be tested for minima and maxima.
C) is parabolic.
D) is quadratic.