Math Problem Statement

The table and scatter plot show the time spent texting, x, and the time spent exercising, y, by each of 9 students last week. Using the equation of the line of best fit, ŷ = -0.5x + 7.64, fill in the blanks with exact answers for the predicted and residual times spent exercising for x = 4.10 and x = 5.00.

Solution

To solve the problem, we need to analyze the data and equation provided.

The equation of the line of best fit is:

y^=0.5x+7.64\hat{y} = -0.5x + 7.64

Where:

  • xx is the time spent texting (in hours),
  • y^\hat{y} is the predicted time spent exercising (in hours).

Step-by-Step Breakdown:

  1. Predict the time spent exercising: Use the equation y^=0.5x+7.64\hat{y} = -0.5x + 7.64 to find the predicted values for x=4.10x = 4.10 and x=5.00x = 5.00.

  2. Calculate the residual: The residual is the difference between the observed time spent exercising and the predicted time spent exercising:

    Residual=ObservedPredicted\text{Residual} = \text{Observed} - \text{Predicted}


1. For x=4.10x = 4.10:

  • Predicted time spent exercising: y^=0.5(4.10)+7.64=2.05+7.64=5.59hours\hat{y} = -0.5(4.10) + 7.64 = -2.05 + 7.64 = 5.59 \, \text{hours}
  • Observed time spent exercising: From the table, the observed value for x=4.10x = 4.10 is y=5.59y = 5.59 hours.
  • Residual: Residual=5.595.59=0\text{Residual} = 5.59 - 5.59 = 0

2. For x=5.00x = 5.00:

  • Predicted time spent exercising: y^=0.5(5.00)+7.64=2.5+7.64=5.14hours\hat{y} = -0.5(5.00) + 7.64 = -2.5 + 7.64 = 5.14 \, \text{hours}
  • Observed time spent exercising: From the table, the observed value for x=5.00x = 5.00 is y=6.32y = 6.32 hours.
  • Residual: Residual=6.325.14=1.18hours\text{Residual} = 6.32 - 5.14 = 1.18 \, \text{hours}

Summary Table:

Time spent texting (in hours)Observed time spent exercising (in hours)Predicted time spent exercising (in hours)Residual (in hours)
4.105.595.590
5.006.325.141.18

Let me know if you need further details or have any questions.

5 Related Questions:

  1. How is the line of best fit calculated from a set of data points?
  2. What are the uses of residuals in regression analysis?
  3. How do you determine whether a line of best fit is accurate for given data?
  4. What is the significance of a residual of zero?
  5. How would you calculate residuals for other values of time spent texting?

Tip:

Residuals help to show how well the predicted values match the actual data. A residual close to zero indicates a good fit between the prediction and observation.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Linear Regression
Residuals
Scatter Plots

Formulas

ŷ = -0.5x + 7.64 (Equation of line of best fit)
Residual = Observed - Predicted

Theorems

Linear regression and best fit line

Suitable Grade Level

Grades 9-12