In: Statistics and Probability
One of the questions most frequently asked by prospective home buyers along the east coast of the United States is: | ||||
If we purchase this home, how much can we expect to pay to heat it during the winter? The research department | ||||
at Herrington Real Estate has collected the following information. Temperature = Mean Outside Temperature (F); | ||||
Attic = Attic insulation (in inches). | ||||
Home | Mean Outside Temperature (degrees) | Attic Insulation (inches) | Monthly Heating Costs ($) | |
1 | 18 | 3 | 188 | |
2 | 34 | 2 | 256 | |
3 | 36 | 7 | 127 | |
4 | 60 | 6 | 239 | |
5 | 65 | 5 | 190 | |
6 | 20 | 5 | 180 | |
7 | 10 | 6 | 210 | |
8 | 7 | 9 | 260 | |
9 | 21 | 4 | 255 | |
10 | 35 | 6 | 160 | |
11 | 54 | 12 | 100 | |
12 | 26 | 8 | 105 | |
13 | 25 | 3 | 375 | |
14 | 39 | 4 | 250 | |
According to your equation, for every one inch increase in the number of inches of attic insulation, monthly heating | |||||
costs (increase / do not change / decrease) by _____________. Round appropriately. Include the units! (8 pts.) | |||||
According to your equation, if you want your house's monthly heating costs to be $200/month, how many inches of | |||||
attic insulation do you need to have? (4 pts.) Round correctly and include the units. | |||||
Are monthly heating costs statistically related to the number of inches of attic insulation? Test at the .05 level of significance: | |||||
State H0 and H1. | |||||
Obtain the appropriate output. | |||||
According to your equation, for every one inch increase in the number of inches of attic insulation, monthly heating costs decrease by $16.68. Round appropriately. Include the units! (8 pts.)
According to your equation, if you want your house's monthly heating costs to be $200/month, how many inches of attic insulation do you need to have? (4 pts.) Round correctly and include the units.
6.12 inches
Are monthly heating costs statistically related to the number of inches of attic insulation? Test at the .05 level of significance:
The hypothesis being tested is:
H0: β1 = 0
H1: β1 ≠ 0
The p-value is 0.0217.
Since the p-value (0.0217) is less than the significance level (0.05), we can reject the null hypothesis.
Therefore, we can conclude that monthly heating costs is statistically related to the number of inches of attic insulation.
r² | 0.367 | |||||
r | -0.606 | |||||
Std. Error | 60.982 | |||||
n | 14 | |||||
k | 1 | |||||
Dep. Var. | Monthly Heating Costs ($) | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 25,834.9371 | 1 | 25,834.9371 | 6.95 | .0217 | |
Residual | 44,625.4200 | 12 | 3,718.7850 | |||
Total | 70,460.3571 | 13 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=12) | p-value | 95% lower | 95% upper |
Intercept | 302.1000 | |||||
Attic Insulation (inches) | -16.6800 | 6.3284 | -2.636 | .0217 | -30.4684 | -2.8916 |
Please give me a thumbs-up if this helps you out. Thank you!