Math Problem Statement

Given the linear regression equation y = -3x + 2, if the actual value of y is given when x = 3, what is the residual?

Solution

The question you're asking involves finding the residual for a linear regression equation, y=3x+2y = -3x + 2, when x=3x = 3 and the actual value of yy is provided.

To calculate the residual, follow these steps:

  1. Find the predicted yy: Using the equation of the line, substitute x=3x = 3 into the regression equation to calculate the predicted value of yy.

ypred=3(3)+2=9+2=7y_{\text{pred}} = -3(3) + 2 = -9 + 2 = -7

  1. Use the given actual value of yy: The actual value of yy will be provided in the problem statement. For this example, if the actual y=4y = -4, we can now calculate the residual.

  2. Calculate the residual: The residual is the difference between the actual value and the predicted value of yy:

Residual=yactualypred=4(7)=4+7=3\text{Residual} = y_{\text{actual}} - y_{\text{pred}} = -4 - (-7) = -4 + 7 = 3

Thus, the residual is 33.

If you'd like, you can let me know the actual value of yy to complete the calculation or if you'd like further clarification.

Here are five related questions to consider:

  1. How does a residual help assess the fit of a regression model?
  2. What are some other ways to visualize residuals in linear regression?
  3. How would the residual change if the predicted value were off by a larger margin?
  4. What is the difference between a residual and an error in regression analysis?
  5. How can you use residuals to detect outliers in regression data?

Tip: Always check for any data points that produce large residuals—they could indicate outliers or points where the model doesn't fit well!

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Residuals
Algebra

Formulas

y = mx + b
Residual = y_actual - y_pred

Theorems

The concept of residuals in regression analysis

Suitable Grade Level

Grades 9-11