Question

Data from a small bookstore are shown in the accompanying table. The manager wants to predict Sales from Number of Sales People Working. Complete parts a through h below Data Table Number of salesSales (in $1000) 10 12 14 15 18 20 20 24 24 26 y 18.3 SD(y) = 5.46 4 10 10 13 15 15 18 x-10.2 SD(x)-5.37 |

Answer 1

The line of regresson is

Find X. Y and X2 as it was done in the table below X.Y 20 48 70 135 180 200 260 360 384 468 X. X 4 16 25 81 100 100 169 225 256 324 2 18 20 20 24 24 26 18 Find the sum of every columrn X-102, ΣΥ-183, ΣΧ.Y-2125, ΣΧ-1300 Use the following equations to find a and b ΣΥ . Σ x2-. Σχ . ΣΧΥ 183 . 1300-102-2125 10.1300 1022 n . ΣΧΥ-Σχ . ΣΥ 10 . 2125-102-183 10 1300 (102)2 Substitute a and b in regression equation formula y = 8.147 + 0.995-

a) b1 = 0.995

b) An additional $995 of sales is associated with each additional sales person working.

c) b0 = 8.147

d) On average $8,147 is expected when 0 sales people are working. It is not meaningful because is doesnot make a sense un this context

e) $\widehat{Sales} = 8.147+0.995* (number of sales Person working)$

When X = 17

Est Y = 8.147+0.995*17 = 25.062

The predicted sales for 17 people working is 25,062 S

g) The residual is (25000-25062) =-62 dollars

h) overestimated.