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Students in Mr. Handford’s class dropped a kickball beneath a motion detector. The detector recorded the height of the ball as it bounced up and down several times. Here are the heights of the ball at the highest point on the first five bounces:

Bounce numberHeight (feet)12.24021.62031.23540.95850.756

Here is the scatter plot of the data

(a) The following graphs show the results of two different transformations of the data. Would an exponential model or a power model provide a better description of the relationship between bounce number and height? Justify your answer.

(b) Minitab output from a linear regression analysis on the transformed data of log(height) versus bounce number is shown below. Give the equation of the least-squares regression line. Be sure to define any variables you use.

PredictorCoefSE CoefTPConstant0.453740.0138532.760.000Bounce-0.1171600.004176-28.060.000

S=0.0132043R-Sq=99.6%R-Sq(adj)=99.5%

(c) Use your model from part (b) to predict the highest point the ball reaches on its seventh bounce. Show your work.

(d) A residual plot for the linear regression in part (b) is shown below. Do you expect your prediction part (c) to be too high, too low, or just right? Justify your answer.

Short Answer

Expert verified

(a) The link between bounce number and height is better described by an exponential model.

(b) The equation is logy^=0.45374-0.117160x.

(c) The highest point the ball reaches on its seventh bounce is 0.43015feet.

(d) The prediction is too low.

Step by step solution

01

Part(a) Step 1: Given Information

02

Part(a) Step 2: Explanation

The data about the bounce number and height is provided in the question. As a result, the scatterplot of the model that best describes the link between bounce number and height must have a roughly linear pattern. Because the top graph corresponds to an exponential model and the bottom graph corresponds to a power model, the exponential model will provide a better representation of the link between bounce number and height.

03

Part(b) Step 1: Given Information

PredictorCoefSE CoefTPConstant0.453740.0138532.760.000Bounce-0.1171600.004176-28.060.000

S=0.0132043R-Sq=99.6%R-Sq(adj)=99.5%

04

Part(b) Step 2: Explanation

Now, the query specifies that variable xrepresents the bounce and variable yrepresents the height. As a result, the general equation will be:

localid="1652853437967" logy^=a+bx

The slope and constant of the regression line are given in the question as:

a=0.45374

b=-0.117160

As a result, the regression line appears to be as follows:

localid="1652853637700" logy^=a+bx=0.45374-0.117160x

05

Part(c) Step 1: Given Information

PredictorCoefSE CoefTPConstant0.453740.0138532.760.000Bounce-0.1171600.004176-28.060.000

S=0.0132043R-Sq=99.6%R-Sq(adj)=99.5%

06

Part(c) Step 2: Explanation

The regression line is:

logy^=a+bx=0.45374-0.117160x

calculation to find the highest point is

logy^=a+bx=0.45374-0.117160x=0.45374-0.117160×7=-0.36638=10-0.36638=0.43015

07

Part(d) Step 1: Given Information

08

Part(d) Step 2: Explanation

The regression line is:

logy^=a+bx=0.45374-0.117160x

The question also includes a residual plot of the linear regression in section (b). As a result, we can see a rising pattern in the residual plot for bounces 3, 4, and 5, and the residual will most likely climb even more for bounce seven. It is then assumed that the residual will be positive. As a result, the residual is equal to the actual value minus the anticipated value. The predicted value is supposed to be lower than the actual value since the residual is expected to be positive. As a result, our forecast is too low.

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Most popular questions from this chapter

Some high school physics students dropped a ball and measured the distance fallen (in centimeters) at various times (in seconds) after its release. If you have studied physics, then you probably know that the theoretical relationship between the variables is distance=490(time)2. A scatterplot of the students’ data showed a clear curved pattern. A scatterplot of which of the following should have a roughly linear pattern?

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