Math Problem Statement

Compute the equation of the regression line for a dataset that has the statistics given below. Round the values of a and b to two decimal places. x=9, Sx=1, y=267, Sy=93, r=0.95

Solution

To compute the equation of the regression line, we use the formula for the equation of a line:

y=a+bxy = a + bx

Where:

  • bb is the slope of the regression line, calculated as:

b=r×SySxb = r \times \frac{S_y}{S_x}

  • aa is the y-intercept, calculated using:

a=yˉb×xˉa = \bar{y} - b \times \bar{x}

Given:

  • xˉ=9\bar{x} = 9
  • Sx=1S_x = 1
  • yˉ=267\bar{y} = 267
  • Sy=93S_y = 93
  • r=0.95r = 0.95

Step 1: Calculate the slope bb

b=0.95×931=0.95×93=88.35b = 0.95 \times \frac{93}{1} = 0.95 \times 93 = 88.35

Step 2: Calculate the y-intercept aa

a=267(88.35×9)=267795.15=528.15a = 267 - (88.35 \times 9) = 267 - 795.15 = -528.15

Final Answer:

The equation of the regression line is:

y=528.15+88.35xy = -528.15 + 88.35x

Let me know if you want more details or have any questions.

Here are five related questions to explore further:

  1. How does the correlation coefficient rr affect the slope of the regression line?
  2. What would the regression equation be if the correlation rr were negative?
  3. How can we use the regression equation to make predictions?
  4. What is the interpretation of the y-intercept in a regression line?
  5. How do outliers affect the regression equation?

Tip: The correlation coefficient rr tells you not only the strength of the relationship but also the direction (positive or negative) of the linear relationship between the variables.

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Math Problem Analysis

Mathematical Concepts

Statistics
Linear Regression
Correlation Coefficient

Formulas

Regression line equation: y = a + bx
Slope: b = r × (Sy / Sx)
Intercept: a = ȳ - b × x̄

Theorems

Linear Regression Formula
Correlation Coefficient

Suitable Grade Level

College/University Level