Math Problem Statement

Suppose we want to use data on square footage to predict home sale prices. An equation that fits the data below reasonably well is

Predicted Selling Price=33.14+0.18(Square Footage).

In order to find the sum of squared errors for this data, we have constructed the following table.

Housing Prices and Square Footage Observed Selling Price (Thousands of Dollars) Observed Square Footage Predicted Selling Price (Thousands of Dollars) Error Squared Error 252.7 1209 250.76 1.94 3.7636 286.5 1504 303.86 −17.36 301.3696 271.5 1417 288.20 −16.70 278.8900 224.6 1109 232.76 − 8.16 66.5856 273.3 1212 251.30 22.00 484.0000 316.3 1506 304.22 12.08 145.9264 276.0 1437 291.80 −15.80 249.6400 394.2 1984

Find the missing values in the table for an observed selling price of 394.2 and square footage of 1984 . Round your answers to two decimal places, if necessary.

Solution

We are asked to calculate the missing values for the observed selling price of 394.2 (thousands of dollars) and square footage of 1984, using the provided predicted selling price equation:

Predicted Selling Price = 33.14 + 0.18(Square Footage)

Step-by-step calculation:

  1. Predicted Selling Price:

    • The square footage is 1984.
    • Use the equation to calculate the predicted selling price.

    Predicted Selling Price=33.14+0.18×1984\text{Predicted Selling Price} = 33.14 + 0.18 \times 1984

    Predicted Selling Price=33.14+357.12=390.26 (thousands of dollars)\text{Predicted Selling Price} = 33.14 + 357.12 = 390.26 \text{ (thousands of dollars)}

  2. Error:

    • The observed selling price is 394.2 (thousands of dollars).
    • The error is the difference between the observed and predicted selling prices:

    Error=Observed Selling PricePredicted Selling Price\text{Error} = \text{Observed Selling Price} - \text{Predicted Selling Price}

    Error=394.2390.26=3.94 (thousands of dollars)\text{Error} = 394.2 - 390.26 = 3.94 \text{ (thousands of dollars)}

  3. Squared Error:

    • The squared error is the square of the error value:

    Squared Error=(Error)2\text{Squared Error} = (\text{Error})^2

    Squared Error=(3.94)2=15.5236\text{Squared Error} = (3.94)^2 = 15.5236

Final Table Entry for Observed Selling Price = 394.2 and Square Footage = 1984:

  • Predicted Selling Price = 390.26
  • Error = 3.94
  • Squared Error = 15.52

Would you like me to explain further or solve any related questions? Here are 5 possible related questions to explore:

  1. How do you interpret the squared error in the context of regression analysis?
  2. How would the sum of squared errors change if the predicted prices were off by a larger margin?
  3. What are the steps for calculating the regression line for such data?
  4. How can we assess the accuracy of our model beyond the sum of squared errors?
  5. What would happen to the model's predictions if we used a different formula for predicting the selling price?

Tip: To reduce the sum of squared errors, we can try optimizing the regression model or use techniques like ridge regression or Lasso if multicollinearity is an issue in more complex models.

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Math Problem Analysis

Mathematical Concepts

Regression Analysis
Linear Equation
Error Analysis

Formulas

Predicted Selling Price = 33.14 + 0.18 * Square Footage
Error = Observed Selling Price - Predicted Selling Price
Squared Error = Error^2

Theorems

Least Squares Regression

Suitable Grade Level

Grades 10-12