Chap12_part1

# Chap12_part1 - 528 Chapter 12 Simple Linear Regression...

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16 Chapter 12: Simple Linear Regression CHAPTER 12 12.1 (a) When X = 0, the estimated expected value of Y is 2. (b) For an increase in the value of X by 1 unit, we can expect an increase by an estimated 5 units in the value of Y . (c) ˆ 2 5 2 5(3) 17 Y X = + = + = (d) yes, (e) no, (f) no, (g) yes, (h) no 12.2 (a) When X = 0, the estimated expected value of Y is 16. (b) For increase in the value X by 1 unit, we can expect a decrease by an estimated 0.5 units in the value of Y . (c) 13 ) 6 ( 5 . 0 16 5 . 0 16 ˆ = - = - = X Y 12.3 (a) (b),(c) 0 1.45 b = , 1 0.074 b = For each increase in shelf space of an additional foot, there is an expected increase in weekly sales of an estimated 0.074 hundreds of dollars, or \$7.40. (d) 042 . 2 ) 8 ( 074 . 0 45 . 1 074 . 0 45 . 1 ˆ = + = + = X Y , or \$204.20 (e) 5333 . 1 0 = b , 064 . 0 1 = b For each increase in shelf space of an additional foot, there is an expected increase in weekly sales of an estimated 0.064 hundreds of dollars, or \$6.40. 0453 . 2 ) 8 ( 064 . 0 5333 . 1 064 . 0 5333 . 1 ˆ = + = + = X Y , or \$204.53 (f) The best allocation to pet food depends on the profit made per foot of shelf space. The expected weekly sales (and profits) per foot of shelf space actually declines as the amount of allocated shelf space increases from 5 to 20 feet, however, if the profitability is still high enough, it will be worthwhile assigning a higher amount to pet food. 0 1 2 3 4 0 5 10 15 20 Shelf Space, X Weekly Sales, Y

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17 Chapter 12: Simple Linear Regression 12.4 (a) (b) Partial Excel output: Coefficients Standard Error t Stat P-value Intercept -2.3697 2.0733 -1.1430 0.2610 Feet 0.0501 0.0030 16.5223 0.0000 (c) The estimated average amount of labor will increase by 0.05 hour for each additional cubic foot moved. (d) 2 ( 29 2.3697+0.0501 500 22.6705 Y = - = (e) Other factors that might affect labor hours are size of the movers, how accessible is the building to the moving truck, etc. 12.5 (a) Scatter Diagram 0 5 10 15 20 25 0 200 400 600 800 Weight (lbs.) # of Orders Scatter Diagram 0 10 20 30 40 50 60 70 80 90 0 200 400 600 800 1000 1200 1400 1600 X Y
Solutions to End-of-Section and Chapter Review Problems 18 12.5 (b) ˆ 0.1912 0.0297 Y X = + cont. (c) For each increase of one additional pound, the estimated average number of orders will increase by 29.7. (d) ( 29 ˆ 0.1912 0.0297 500 15.043 Y = + = 12.6 (a) Scatter Plot 0 50 100 150 200 250 300 350 400 0 10 20 30 40 50 60 70 Gross (\$millions) Video Units Sold (thousands) (b),(c) X Y 3331 . 4 54 . 76 ˆ + = (d) For each increase of 1 million dollars in box office gross, expected home video units sold is estimated to increase by 4.3331 thousand, or 4333.1 units. (e) = + = + = ) 20 ( 3331 . 4 54 . 76 3331 . 4 54 . 76 ˆ X Y 163.202 or 163,202 units. (f)

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## This homework help was uploaded on 04/09/2008 for the course ENGR, STAT 320, 262, taught by Professor Harris during the Spring '08 term at Purdue.

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Chap12_part1 - 528 Chapter 12 Simple Linear Regression...

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