Math Problem Statement

Shown below are the scatter plots for four different data sets. Answer the following questions: 1. Which data set has an apparent positive, but not perfect, linear relationship between its two variables? 2. For which data set does the correlation coefficient r appear to be equal to -1? 3. Which data set indicates the strongest linear relationship between its two variables?

Solution

The image contains four scatter plots labeled as Figure 1 through Figure 4 and three corresponding questions. Here's an interpretation of the questions and how to approach them:

  1. Which data set has an apparent positive, but not perfect, linear relationship between its two variables?

    • Look for a scatter plot where the data points show a general upward trend (i.e., as one variable increases, the other tends to increase) but does not form a perfect straight line.
  2. For which data set does the correlation coefficient rr appear to be equal to -1?

    • The correlation coefficient rr is -1 when there is a perfect negative linear relationship, meaning the points lie exactly on a straight line with a negative slope.
  3. Which data set indicates the strongest linear relationship between its two variables?

    • Identify the scatter plot where the points are closest to forming a straight line, whether positive or negative.

Answers Based on the Scatter Plots:

  • Figure 1: Data points seem scattered with no strong relationship, probably no linear correlation.
  • Figure 2: Shows a strong negative linear relationship, where the points are nearly on a straight line. This would likely have r=1r = -1.
  • Figure 3: Also shows a negative linear trend but less tight compared to Figure 2. Still a moderately strong negative correlation.
  • Figure 4: Displays a weak positive linear trend, where the points are spread out but generally increasing.

Suggested Answers:

  1. Positive, but not perfect, linear relationship: Figure 4.
  2. r=1r = -1: Figure 2.
  3. Strongest linear relationship: Figure 2.

Do you need further explanation or have any questions?

Related Questions:

  1. How do you calculate the correlation coefficient rr mathematically?
  2. What does a positive or negative correlation coefficient signify?
  3. How can outliers affect the correlation coefficient?
  4. What is the difference between a strong and weak linear relationship?
  5. How can you use the line of best fit to estimate correlation strength?

Tip:

A correlation coefficient of r=1r = 1 means a perfect positive linear relationship, while r=1r = -1 indicates a perfect negative one.

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Math Problem Analysis

Mathematical Concepts

Statistics
Correlation
Scatter Plots
Linear Relationships

Formulas

Correlation Coefficient (r)

Theorems

Pearson Correlation Theorem

Suitable Grade Level

Grades 9-12