Chapter $4,$ Question $29($correction: the question is asking for the quarters following year $25$ not the quarters of year $25.$ Namely, quarters $101$ to $104.)$:

North Dakota Electric Company estimates its demand trend line $($in millions of kilowatt hours$)$ to be:

D $=77+0\mathrm{.}43$Q

where Q refers to the sequential quarter number and Q $=1$ for winter of Year $1.$ In addition, the multiplicative seasonal factors are as follows:

QUARTER FACTOR $($INDEX$)$

Winter $\mathrm{.}8$

Spring $1\mathrm{.}1$

Summer $1\mathrm{.}4$

Fall $\mathrm{.}7$

Forecast energy use for the four quarters of year $26($namely quarters $101$ to $104),$ beginning with winter.