In working for a local retail store, you have developed the following estimated regression equation:

yn = 22,167 - 412x1 + 818x2 - 93x3 - 71x4 where:

y = Weekly sales x1 = Local unemployment rate x2 = Weekly average high temperature x3 = Number of activities in the local community x4 = Average price of gasoline per gallon

a. Interpret the values of b1, b2, b3, and b4 in this estimated regression equation.

b. What is the estimated sales if the unemployment rate is 5.7%, the average high temperature is 61°, there are 14 activities, and the average price of gasoline is $3.39 per gallon?