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=18.03+0.13(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 189.1 1359 194.70 − 5.60 31.3600 260.2 1910 266.33 − 6.13 37.5769 146.2 1015 149.98 − 3.78 14.2884 250.1 1808 253.07 − 2.97 8.8209 191.2 1329 190.80 0.40 0.1600 202.9 1420 202.63 0.27 0.0729 198.5 1455 207.18 − 8.68 75.3424 223.5 1625

Find the missing values in the table for an observed selling price of 223.5 and square footage of 1625 . Round your answers to two decimal places, if necessary.

Solution

To find the missing values for the observed selling price of 223.5 and square footage of 1625, we need to follow the steps below:

Step 1: Calculate the Predicted Selling Price

We use the equation for the predicted selling price:

Predicted Selling Price=18.03+0.13×(Square Footage)\text{Predicted Selling Price} = 18.03 + 0.13 \times (\text{Square Footage})

Substitute the given square footage of 1625:

Predicted Selling Price=18.03+0.13×1625\text{Predicted Selling Price} = 18.03 + 0.13 \times 1625

Predicted Selling Price=18.03+211.25=229.28 (Thousands of Dollars)\text{Predicted Selling Price} = 18.03 + 211.25 = 229.28 \text{ (Thousands of Dollars)}

Step 2: Calculate the Error

The error is the difference between the observed selling price and the predicted selling price. The observed selling price is given as 223.5.

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

Error=223.5229.28=5.78 (Thousands of Dollars)\text{Error} = 223.5 - 229.28 = -5.78 \text{ (Thousands of Dollars)}

Step 3: Calculate the Squared Error

The squared error is the square of the error:

Squared Error=Error2\text{Squared Error} = \text{Error}^2

Squared Error=(5.78)2=33.45 (Thousands of Dollars squared)\text{Squared Error} = (-5.78)^2 = 33.45 \text{ (Thousands of Dollars squared)}

Final Results

  • Predicted Selling Price: 229.28
  • Error: -5.78
  • Squared Error: 33.45

Would you like further clarification on any of the steps or additional help with another problem? Here's a list of related questions that could help build a deeper understanding of this topic:

  1. How do you interpret the error and squared error in the context of model accuracy?
  2. What is the meaning of the equation used to predict the selling price of a house?
  3. How can we use the sum of squared errors to evaluate the overall fit of the model?
  4. What is the relationship between the square footage of a house and its predicted selling price according to this model?
  5. How can you calculate the coefficient of determination (R-squared) from the sum of squared errors?

Tip: The sum of squared errors (SSE) is an important metric in regression analysis. It helps to measure the total deviation of the predicted values from the observed values. A lower SSE indicates that the model fits the data better.

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Error Calculation
Squared Error

Formulas

Predicted Selling Price = 18.03 + 0.13 × (Square Footage)
Error = Observed Selling Price - Predicted Selling Price
Squared Error = Error^2

Theorems

Least Squares Regression

Suitable Grade Level

Grades 9-12