Math Problem Statement

Data collected from a sample of 8 graduate students relating study time (x in hours per week) and leisure time (y hours per week) yielded the results shown here. Which one of the following represents the equation of the regression line relating y to x?

Solution

To determine the equation of the regression line y^=b1x+b0\hat{y} = b_1x + b_0, we need to calculate the slope b1b_1 and intercept b0b_0 using the given data.

Step 1: Calculate the slope (b1b_1)

The formula for b1b_1 is: b1=SSxySSxxb_1 = \frac{SS_{xy}}{SS_{xx}} Substitute the given values: b1=49.751843.870.027b_1 = \frac{-49.75}{1843.87} \approx -0.027

Step 2: Calculate the intercept (b0b_0)

The formula for b0b_0 is: b0=yˉb1xˉb_0 = \bar{y} - b_1\bar{x} To find xˉ\bar{x} and yˉ\bar{y}: xˉ=ΣXn=4758=59.375\bar{x} = \frac{\Sigma X}{n} = \frac{475}{8} = 59.375 yˉ=ΣYn=608=7.5\bar{y} = \frac{\Sigma Y}{n} = \frac{60}{8} = 7.5

Now substitute into the formula for b0b_0: b0=7.5(0.027)(59.375)b_0 = 7.5 - (-0.027)(59.375) b07.5+1.6031259.1b_0 \approx 7.5 + 1.603125 \approx 9.1

Step 3: Write the equation

The regression equation is: y^=0.027x+9.1\hat{y} = -0.027x + 9.1

Final Answer:

The correct choice is: y-hat = -0.027x + 9.1\text{y-hat = -0.027x + 9.1}

Would you like a detailed explanation of any of the steps? Here are some related questions you might find helpful:

  1. How do you interpret the slope and intercept in this context?
  2. What are some real-world applications of regression equations?
  3. How do residuals relate to the regression line?
  4. How can the coefficient of determination (R2R^2) be calculated and interpreted?
  5. What assumptions are made in a simple linear regression model?

Tip: Always check for units and the context of your variables to make meaningful interpretations of the regression equation!

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Math Problem Analysis

Mathematical Concepts

Linear Regression
Statistics
Slope-Intercept Form

Formulas

b1 = SSxy / SSxx
b0 = ȳ - b1x̄
Regression Equation: ŷ = b1x + b0

Theorems

Least Squares Regression

Suitable Grade Level

Undergraduate