# Linear Regression and Correlation

## Prediction (Optional)

Recall the third exam/final exam example.
We found the equation of the best-fit line for the final exam grade as a function of the grade on the third exam. We can now use the least-squares regression line for prediction.
Suppose you want to estimate, or predict, the mean final exam score of statistics students who received a 73 on the third exam. The exam scores (x values) range from 65 to 75. Since 73 is between the x values 65 and 75, substitute x = 73 into the equation. Then,
We predict that statistics students who earn a grade of 73 on the third exam will earn a grade of 179.08 on the final exam, on average.

### References

Centers for Disease Control and Prevention. (n.d.). Retrieved from https://www.cdc.gov/
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention. (n.d.). Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/nchhstp/default.htm
National Center for Health Statistics. (n.d.). Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/nchs/index.htm
U.S. Census Bureau. (n.d.). Retrieved from http://www.census.gov/compendia/statab/cats/transportation/motor_vehicle_accidents_and_fatalities.html

### Chapter Review

After determining the presence of a strong correlation coefficient and calculating the line of best fit, you can use the least-squares regression line to make predictions about your data.
Use the following information to answer the next two exercises. An electronics retailer used regression to find a simple model to predict sales growth in the first quarter of the new year (January through March). The model is good for 90 days, where x is the day. The model can be written as ŷ = 101.32 + 2.48x, where ŷ is in thousands of dollars.
Use the following information to answer the next three exercises. A landscaping company is hired to mow the grass for several large properties. The total area of the properties is 1,345 acres. The rate at which one person can mow is ŷ = 1350 – 1.2x, where x is the number of hours and ŷ represents the number of acres left to mow.
Use the following information to answer the next 14 exercises.  contains real data for the first two decades of flu reporting.

### Homework
