a. Is a line an appropriate model to use for these data? Explain how you know.

b. Find the correlation.

c. What is the equation of the least-squares regression line? Define any variables that you

use.

d. Interpret the values of s and r2.

More mess? When Mentos are dropped into a newly opened bottle of Diet

Coke, carbon dioxide is released from the Diet Coke very rapidly, causing the Diet Coke to be expelled from the bottle. To see if using more Mentos causes more Diet Coke to be expelled, Brittany and Allie used twenty-four 2-cup bottles of Diet Coke and randomly assigned each bottle to receive either 2, 3, 4, or 5 Mentos. After waiting for the fizzing to stop, they measured the amount expelled (in cups) by subtracting the amount remaining from the original amount in the bottle.29 Here is some computer output from a regression of y = amount expelled on x = number of Mentos:

a. Is a line an appropriate model to use for these data? Explain how you know.

b. Find the correlation.

c. What is the equation of the least-squares regression line? Define any variables that you use.

d. Interpret the values of s and r2.

Short Answer

Expert verified

Part (a) Yes, a line appears to be appropriate for these data.

Part (b)r=0.7760

Part (c) y=1.0021+0.0708x

Part (d) The least square regression line utilizing the number of Mentos as an explanatory variable can explain 60.21 percent of the variation in the amount ejected.

Step by step solution

01

Part (a) Step 1: Given information

02

Part (a) Step 2: Explanation

The question specifies the relationship between the number of Mentos consumed and the amount of cocaine ejected. For the same, a scatterplot and a residual plot are provided. Because there is no substantial curvature in the scatterplot and no strong curvature in the residual plot, it appears that a line is appropriate for these data.

03

Part (b) Step 1: Explanation

The relationship between the number of Mentos and the amount of coke expelled is given in the question. The scatterplot and the residual plot for the same are given. Thus, the coefficient of determination is given in the computer output after “R-Sq” as:

r2=60.21%=0.6021

The positive or negative square root of the coefficient of determination r yields the linear correlation coefficient r. As a result, we can see that the scatterplot pattern slopes upwards, indicating a positive relationship between the variables and hence a positive linear correlation coefficient rThis indicates that,

r=+r2=+0.6021=0.7760

04

Part (c) Step 1: Explanation

The question specifies the relationship between the number of Mentos consumed and the amount of cocaine ejected. For the same, a scatterplot and a residual plot are provided. The least-square regression line's general equation is:

y=b0+b1x

As a result, the estimate of the constant b0 is given in the computer output's row "Constant" and column "Coef" as:

b0=1.0021

In the computer output, the estimate of the slope b1 is presented in the row "Mentos" and the column "Coef" as:

b1=0.0708

Thus, putting the values in the general equation we will get,

y=b0+b1x

y=1.0021+0.0708x

05

Part (d) Step 1: Explanation

The question specifies the relationship between the number of Mentos consumed and the amount of cocaine ejected. For the same, a scatterplot and a residual plot are provided. As a result, after "S="in the computer output, the standard error of the estimations is given as:

s=0.6724

The standard error of the estimations, as we all know, is the average error of forecasts, and thus the average difference between actual and predicted values. As a result, the predicted amount evacuated using the equation of the least square regression line was 0.6724 cups less than the actual amount expelled on average.

In the computer output, the coefficient of determination is now given after "R-Sq"as:

r2=60.21%=0.6021

The coefficient of determination, as we all know, represents the proportion of variance in the answers y variable that can be explained by a least square regression model using the explanatory x variable. As a result, the least square regression line utilizing the number of Mentos as an explanatory variable can explain 60.21 percent of the variation in the amount ejected.

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Most popular questions from this chapter

Calculating achievement a study found a strong link between the number of calculators possessed by high school pupils and their arithmetic proficiency, according to the principle of a high school. Based on this study, he decides to buy each student at his school two calculators, hoping to improve their math achievement. Explain the flaw in the principal’s reasoning.

A school guidance counselor examines how many extracurricular activities students participate in and their grade point average. The guidance counselor says, “The evidence indicates the correlation between the number of extracurricular activities. a student participates in and his or her grade point average is close to 0.” Which of the following is the most appropriate conclusion?

a. Students involved in many extracurricular activities tend to be students with poor grades.

b. Students with good grades tend to be students who are not involved in many extracurricular activities.

c. Students involved in many extracurricular activities are just as likely to get good grades as bad grades.

d. Students with good grades tend to be students who are involved in many

extracurricular activities.

e. No conclusion should be made based on the correlation without looking at a scatterplot of the data.

Suppose that the measurements of arm span and height were converted from centimeters to meters by dividing each measurement by 100. How will this conversion affect the values of r2 and s?

a. r2 will increase, s will increase.

b. r2 will increase, s will stay the same.

c. r2 will increase, s will decrease.

d. r2 will stay the same, s will stay the same.

e. r2 will stay the same, s will decrease.

Manatees are large, gentle, slow-moving sea creatures found along the coast of Florida. Many manatees are injured or killed by boats. Here is a scatterplot showing the relationship between the number of boats registered in Florida (in thousands) and the number of manatees killed by boats for the years 1977 to 2015.13Isr>0orr<0? Closer to r=0orr=±1?Explain your reasoning.

Which of the following is not a characteristic of the least-squares regression line?

a. The slope of the least-squares regression line is always between –1 and 1.

b. The least-squares regression line always goes through the point (x¯,y¯) .

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