Suppose number soft drinks sold at soccer games results in r

Suppose number soft drinks sold at soccer games results in regression estimate sd= -240 + 8x where sd is number sold and x is temperature in degrees Farenheit. a.What is interpretation of b₁ and does this make practical sense? b. What is estimated number soft drinks that would be sold if temperature is 80 degrees Farenheit? c. At what temperature are predicted sales equal to zero?

Solution

Given regression line is sd = -240 + 8x

Comparing the above equation with standard regression line y = b0 + b1(x) we get b0 = -240 and b1 = 8.

a) Here b1 is the SLOPE of the regression line. Thus this is the amount that the no. of soft drink sold will change for each 1 unit change in the degree farenheit. It does make practical sense, as every degree farenhite change in temperature will result in 8 no. of soft drink sale.

b) for temperature = x = 80 degree farenhite

sd = -240 + 8*80 = -240 + 640 = 400

Thus, the estimated no. of cold drinks sold at 80 degree farenhite is 400.

c) For predict sales to be zero,

sd = -240 + 8x = 0

solving above we get, 8x = 240

or, x = 30.

So for temperature of 30 degree Farenhite, the sales will be equal to zero.