Researchers continue to look for methods to estimate how fast a car was traveling before an accident. Most methods focus on the distance to completely stop a car at various speeds. Consider the following data.
|
MPH
|
Braking distance in feet
|
|
20
|
20
|
|
30
|
52
|
|
40
|
81
|
|
50
|
158
|
|
60
|
205
|
|
80
|
411
|
1. Using Statcrunch or your calculator, created a fitted line plot. Print and include this or reproduce an accurate sketch.
2. Describe the form, strength, and direction of this relationship.
3. Then compute the correlation coefficient (r). What is the value? Explain in a few sentences whether or not this value makes sense based on what you wrote in part 2.
4. Compute the linear model using StatCrunch or your calculator.
5. Explain what the slope means and what the y-intercept means in the context of the problem.
6. Use the model to predict the breaking distance for a car traveling at 90 mph.
7. Using the model, determine and interpret the residual for 80 mph.