You’ve just performed a linear regression on the quantity of athletic socks sold during sales targeting customers who have made New Year’s resolutions to get fit. If you have an intercept of 821 and a slope of -25, how many socks would you estimate will be sold when the price is $6?

 
 
 
 
 
 

Using the formula US = a + b*Pi, you’ve correctly estimated that the number of socks sold at $6 is 671.