$4.$ An electrical contractor's records during the last five weeks indicate the number of job requests:

Week

$1$

$20$

$2$

$3$

$4$

$5$

Requests

$22$

$18$

$21$

$22$

Predict the number of requests for week $6$ using each of these methods:

a$.$ Naive

b$.$ A four$-$period moving average

c$.$ Exponential smoothing with a $=\mathrm{.}30$; use $20$ for week $2$ forecast

$5.$ A cosmetics manufacturer's marketing department has developed a linear trend equation that can be used to predict annual sales of its popular Hand & Foot Cream.

F$=80+151$

where

F$=$ Annual sales $(000$ bottles$)$

I is in years

a$.$ Are annual sales increasing or decreasing? By how much?

b$.$ Predict annual sales for year $6$ using the equation.