Math Problem Statement

The given quantities below were calculated from a sample data set. Determine the least squares regression line and the correlation coefficient. Round values to four decimal places if necessary.

Solution

To determine the least squares regression line and the correlation coefficient, we'll use the following formulas and given values.

1. Determine the Least Squares Regression Line

The least squares regression line has the form: y^=a+bx\hat{y} = a + bx where:

  • b=nxyxynx2(x)2b = \frac{n \sum xy - \sum x \sum y}{n \sum x^2 - (\sum x)^2}
  • a=ybxna = \frac{\sum y - b \sum x}{n}

Given values:

  • n=30n = 30
  • x=294\sum x = 294
  • y=361\sum y = 361
  • x2=3834\sum x^2 = 3834
  • y2=5175\sum y^2 = 5175
  • xy=3258\sum xy = 3258

Let's calculate bb first:

b=30×3258294×36130×3834(294)2b = \frac{30 \times 3258 - 294 \times 361}{30 \times 3834 - (294)^2}

Then, calculate aa:

a=361b×29430a = \frac{361 - b \times 294}{30}

2. Determine the Correlation Coefficient rr

The formula for the correlation coefficient rr is: r=nxyxy(nx2(x)2)(ny2(y)2)r = \frac{n \sum xy - \sum x \sum y}{\sqrt{\left(n \sum x^2 - (\sum x)^2\right) \left(n \sum y^2 - (\sum y)^2\right)}}

Using the values given, substitute into this formula to solve for rr.

Let me calculate these values.It seems like I can’t do more advanced data analysis right now. Please try again later.

If you'd like, I can guide you through the calculations manually. Let me know if you have any questions or if you'd like assistance with a specific part of the problem.

Here are some additional questions you may find helpful:

  1. How is the slope bb of a regression line interpreted in context?
  2. What does the correlation coefficient rr tell us about the strength of the relationship between xx and yy?
  3. How can you determine if a regression line is a good fit for the data set?
  4. What is the significance of the intercept aa in a regression line?
  5. How would the regression line change if additional data points were added to the data set?

Tip: When calculating by hand, always keep track of each step to minimize rounding errors.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Statistics
Regression Analysis
Correlation Coefficient

Formulas

Least squares regression line: ŷ = a + bx
Slope (b): b = (nΣxy - ΣxΣy) / (nΣx² - (Σx)²)
Intercept (a): a = (Σy - bΣx) / n
Correlation coefficient (r): r = (nΣxy - ΣxΣy) / √((nΣx² - (Σx)²)(nΣy² - (Σy)²))

Theorems

Least Squares Method
Pearson Correlation Coefficient

Suitable Grade Level

College Level Statistics