Exam 13: Correlation and Linear Regression

Ten used cars from a rental fleet are randomly selected.Each vehicle's annual maintenance cost from the previous calendar year (y) is recorded as well as the vehicle's current mileage (x).A simple linear regression is conducted on the data. ​ ​ What is a 98% confidence interval for the mean annual repair cost of all used vehicles with 22,500 miles.=> (Given: Sxx= 8,036,677,024 and = $43,627.700.)

This histogram shows residuals from a simple linear regression: It appears that:

Ten used cars from a rental fleet are randomly selected.Each vehicle's annual maintenance cost from the previous calendar year (y) is recorded as well as the vehicle's current mileage (x).A simple linear regression is conducted on the data. ​ Conduct a test of hypothesis to see if there is sufficient evidence to conclude that used vehicles with 22,500 miles will have a mean annual maintenance cost that exceeds $400.Select the appropriate critical value (CV), test statistic (TS), and decision.(Use α = 0.05).(Given: Sxx= 803,667,7024 and = $43,627.700.)

In a simple linear regression analysis, the standard error of the slope is:

Suppose , where .This is:

The regression equation is y1 = 0.33 + 0.866 x1 ​ ​ Based on this regression summary, what is r2?

We record the amount of time (xin minutes) per day that a group of 12 high school students spend using their cell phone (texting, talking, and web use).We also record the overall GPA (y) of each student.Following is a regression summary for these data: ​ ​ What is a 90% confidence interval for β0, the mean GPA of high school students who spent no time using their cell phone?

Factors A and B show a correlation of 0.95.This means that:

If all the values of an independent variable x are equal, then performing a simple linear regression on a dependent variable y will result in a coefficient of determination that is equal to:

In a deterministic relationship between two variables x and y of the form it is understood that:

The amount of variability explained by the regression model is:

Concerning the simple linear regression model, SST can be expressed as:

Based on the following scatter plot of age versus blood pressure, which of the regression assumptions may be violated?

In simple linear regression, the plot of residuals versus fitted values can be used to check for:

Assume a least-squares regression line is found to be y = -5.73 + 0.282x.The coefficient of determination for these data is 0.64.What is the correlation coefficient?

A simple linear regression between y (weight in pounds) and x (height in inches) results in the following least-squares line: y = 128 + 6x.This tells us that if the height is increased by 1 in, then.on average.the weight is predicted to:

The linear relationship (where and are constants) is an example of: