MATH 215 - Statistical Concepts

Application Assignment #5 - 20 points

Part 1) Life Expectancy and Obesity (16 points)

Review the Health data given in the Excel spreadsheet, named as MATH215-DATA for Application Assignment-5. The variable of % Obesity is the percent of obese residents per state, and the Life Expectancy variable is the average life expectancy in years per state.

1. Create a scatterplot to see the relationship between the variables % Obese and Life Expectancy. [Hint: you might consider changing the x-axis scale] Copy and paste your graph here, and answer the following questions.

a. What is the independent variable?b. What is the dependent variable?c. Does there seem to be a linear association between the two variables?

2. Find the correlation coefficient, r and describe the relationship between % Obese and Life Expectancy. Round your answer to 3 decimals. Is the relationship positive or negative; strong, moderate, or weak?

3. Find the equation of the estimated linear regression line, . Write the equation below and sketch it on the scatter plot.

4. If the %Obese in a state is 30.5% what would you predict the average Life Expectancy of that state to be? (Use the estimated linear regression line, , in question 3)

5. Can 45% Obese be used to estimate the average Life Expectancy for a state? Why or why not?

6. A. Choose one of the provided states in the Excel file and identify the %Obese and Life Expectancy in that state.

What is the state you chose? ______________

What is the %Obese in that state? ___________

What is the Life Expectancy in that state?_______________

B. Find the estimated average Life Expectancy in this state using the estimated regression line .

C. Is the estimated average Life Expectancy in this state higher or lower than the actual Life Expectancy?

7. By how much will Life Expectancy change with one unit increase in % Obese?

8. If the average Life Expectancy of a state is 75.9 years, what would you expect the %Obese of that state to be? (Use the estimated linear regression line, , in question 3)

Part 2) Student Interpretation and Reflection - 4 pts

Write a summary of your learning from this assignment by addressing the following questions:

Based on the analysis performed above, what can be said about the relationship between % Obese and the average Life Expectancy in years? How did the regression analysis you completed above help you understand the relationship?

Include a few sentences in your summary about whether %Obese and Life Expectancy have any causal relationship. Explain.