Regression Analysis and Super Grocery Stores
Chap 13
44
1.4 100 1.3 110 1.3 110 0.8 85 1.2 105 1.2 105 1.1 120 0.9 75 1.4 80 1.1 70 1.0 105 1.1 95
A sample of 12 homes sold last week in St. Paul, Minnesota, is selected. Can we conclude that, as the size of the home (reported below in thousands of square feet) increases, the selling price (reported in $ thousands) also increases?
* Compute the coefficient of correlation. * = [12(1344) – (13.8)(1160)]/12(16.26) – (13.8)2][12(114850) – (1160)2]=0.30722 * Determine the coefficient of determination * r2 = 256.4103/2716.667=0.09438 * df = 12 -2 = 10 * table b2 t = 1.812; Reject the H0 if t > 1.812 * t = r ((n – 2)1/2) / (1 – r2)1/2 = (0.307220(10))1/2/(1-0.094384)1/2 = 0.9715/0.951663 = 1.028 * Accept H0. There is no relationship between the size of the home and the selling price.
58
A dog trainer is exploring the relationship between the size of the dog (weight in pounds) and its daily food consumption (measured in standard cups). Below is the result of a sample of 18 observations.
1 41 3
2 148 8
3 79 5
4 41 4
5 85 5
6 111 6
7 37 3
8 111 6
9 41 3
10 91 5
11 109 6
12 207 10
13 49 3
14 113 6
15 84 5
16 95 5
17 57 4
18 168 9
* Compute the correlation coefficient. Is it reasonable to conclude that the correlation in the population is greater than zero? Use the .05 significance level * r = [18(10496) – (1667)(96)]/ [18(192159) – (1667)2][18(582) – (96)2]=0.987 * Y = -29.7 + 22.93x * Approximately 25 lb weight change * Dog 12 is overeating
Chapter 14
Fran’s Convenience Marts are located throughout metropolitan Erie, Pennsylvania. Fran, the owner, would like to expand into other communities in northwestern Pennsylvania and southwestern New York, such as Jamestown, Corry, Meadville, and Warren. To prepare her
44
1.4 100 1.3 110 1.3 110 0.8 85 1.2 105 1.2 105 1.1 120 0.9 75 1.4 80 1.1 70 1.0 105 1.1 95
A sample of 12 homes sold last week in St. Paul, Minnesota, is selected. Can we conclude that, as the size of the home (reported below in thousands of square feet) increases, the selling price (reported in $ thousands) also increases?
* Compute the coefficient of correlation. * = [12(1344) – (13.8)(1160)]/12(16.26) – (13.8)2][12(114850) – (1160)2]=0.30722 * Determine the coefficient of determination * r2 = 256.4103/2716.667=0.09438 * df = 12 -2 = 10 * table b2 t = 1.812; Reject the H0 if t > 1.812 * t = r ((n – 2)1/2) / (1 – r2)1/2 = (0.307220(10))1/2/(1-0.094384)1/2 = 0.9715/0.951663 = 1.028 * Accept H0. There is no relationship between the size of the home and the selling price.
58
A dog trainer is exploring the relationship between the size of the dog (weight in pounds) and its daily food consumption (measured in standard cups). Below is the result of a sample of 18 observations.
1 41 3
2 148 8
3 79 5
4 41 4
5 85 5
6 111 6
7 37 3
8 111 6
9 41 3
10 91 5
11 109 6
12 207 10
13 49 3
14 113 6
15 84 5
16 95 5
17 57 4
18 168 9
* Compute the correlation coefficient. Is it reasonable to conclude that the correlation in the population is greater than zero? Use the .05 significance level * r = [18(10496) – (1667)(96)]/ [18(192159) – (1667)2][18(582) – (96)2]=0.987 * Y = -29.7 + 22.93x * Approximately 25 lb weight change * Dog 12 is overeating
Chapter 14
Fran’s Convenience Marts are located throughout metropolitan Erie, Pennsylvania. Fran, the owner, would like to expand into other communities in northwestern Pennsylvania and southwestern New York, such as Jamestown, Corry, Meadville, and Warren. To prepare her