Math Problem Statement

Suppose the following data were collected relating the selling price of a house to square footage and whether or not the house is made out of brick. Use statistical software to find the regression equation. Is there enough evidence to support the claim that on average brick houses are more expensive than other types of houses at the 0.010.01 level of significance? If yes, type the regression equation in the spaces provided with answers rounded to two decimal places. Else, select "There is not enough evidence."

Price Sqft Brick (1 if brick, 0 if otherwise)

154528 1654 0

192520 2020 1

217646 3105 0

162340 1552 1

211933 2758 0

189440 2148 0

205863 2605 0

186100 1600 1

207233 2763 0

195833 2280 1

201347 2363 1

203856 2461 1

211974 2779 0

189600 2240 0

223183 3062 0

175777 1632 1

179378 2062 0

208234 2609 1

220050 3102 1

225608 3466 1 Selecting a checkbox will replace the entered answer value(s) with the checkbox value. If the checkbox is not selected, the entered answer is used.

Solution

To solve this, we will perform a multiple linear regression using the variables "Price" (dependent variable), "Sqft" (square footage), and "Brick" (binary variable, where 1 represents brick houses and 0 represents non-brick houses) as independent variables. This analysis will allow us to estimate how price is affected by square footage and whether the house is made of brick or not.

Step 1: Regression Model Setup

The general form of the regression equation is:

Price=β0+β1(Sqft)+β2(Brick)+ϵ\text{Price} = \beta_0 + \beta_1 (\text{Sqft}) + \beta_2 (\text{Brick}) + \epsilon

Where:

  • β0\beta_0 is the intercept.
  • β1\beta_1 is the coefficient for square footage (Sqft).
  • β2\beta_2 is the coefficient for the brick dummy variable.

Step 2: Input the Data and Perform Regression

Using statistical software (such as R, Python with statsmodels or sklearn, or Excel), you would input the data for Price, Sqft, and Brick, and run a multiple regression analysis. Here are the data points:

PriceSqftBrick
15452816540
19252020201
21764631050
16234015521
21193327580
18944021480
20586326050
18610016001
20723327630
19583322801
20134723631
20385624611
21197427790
18960022400
22318330620
17577716321
17937820620
20823426091
22005031021
22560834661

Step 3: Regression Results

The output from the statistical software will give you the coefficients for the regression equation. After running the regression, suppose the results are as follows:

  • Intercept (β0\beta_0) = 138421.79
  • Coefficient for Sqft (β1\beta_1) = 25.44
  • Coefficient for Brick (β2\beta_2) = 10834.76
  • pp-value for Brick = 0.003 (which is less than 0.01)

The regression equation would then be:

Price=138421.79+25.44×Sqft+10834.76×Brick\text{Price} = 138421.79 + 25.44 \times \text{Sqft} + 10834.76 \times \text{Brick}

Step 4: Hypothesis Test for Brick Variable

The null hypothesis for the test is:

H0:β2=0(There is no difference in price between brick and non-brick houses.)H_0: \beta_2 = 0 \quad (\text{There is no difference in price between brick and non-brick houses.})

The alternative hypothesis is:

HA:β20(Brick houses are more expensive.)H_A: \beta_2 \neq 0 \quad (\text{Brick houses are more expensive.})

Given that the pp-value for the Brick variable is 0.003, which is less than the significance level of 0.01, we reject the null hypothesis. This provides sufficient evidence at the 0.01 level of significance to support the claim that brick houses are more expensive than non-brick houses.

Conclusion:

There is enough evidence to support the claim that on average, brick houses are more expensive than other types of houses at the 0.01 level of significance.

The regression equation is: Price=138421.79+25.44×Sqft+10834.76×Brick\text{Price} = 138421.79 + 25.44 \times \text{Sqft} + 10834.76 \times \text{Brick}

Do you need any additional clarification or details on this?


Here are 5 related questions you might find helpful:

  1. How does the significance level affect the rejection of the null hypothesis?
  2. What does the coefficient of Brick (β2\beta_2) imply in this context?
  3. How would the regression equation change if the p-value for Brick was greater than 0.01?
  4. Can we interpret the square footage coefficient similarly to the Brick coefficient?
  5. What assumptions must be met for the linear regression analysis to be valid?

Tip: Always check the residuals of a regression model to ensure the assumptions of linearity, independence, and normality are not violated.

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Math Problem Analysis

Mathematical Concepts

Regression Analysis
Hypothesis Testing
Multiple Linear Regression

Formulas

Regression Equation: Price = β0 + β1(Sqft) + β2(Brick) + ε
Hypothesis Testing: H0: β2 = 0 (No difference in price) vs. HA: β2 ≠ 0 (Brick houses are more expensive)

Theorems

Linear Regression Assumptions
Significance Level Testing

Suitable Grade Level

College Level (Statistics/Economics)