Questions from Business Statistics

Q: Here are the residuals for a regression of Sales on Number of

Here are the residuals for a regression of Sales on Number of Sales People Working for the bookstore of Exercise 5: 1. What are the units of the residuals? 2. Which residual contributes the most to th...

Q: An analysis of spending by a sample of credit card bank cardholders

An analysis of spending by a sample of credit card bank cardholders shows that spending by cardholders in January (Jan) is related to their spending in December (Dec): The assumptions and conditions o...

Q: The researcher in Exercise 9 is content with the second regression.

The researcher in Exercise 9 is content with the second regression. But he has found a number of shells that have large residuals and is considering removing all of them. Is this good practice?

Q: There is a strong correlation between the temperature and the number of

There is a strong correlation between the temperature and the number of skinned knees on playgrounds. Does this tell us that warm weather causes children to trip?

Q: The correlation between cell phone usage and life expectancy is very high

The correlation between cell phone usage and life expectancy is very high. Should we buy cell phones to help people live longer?

Q: A team of calculus teachers is analyzing student scores on a final

A team of calculus teachers is analyzing student scores on a final exam compared to the midterm scores. One teacher proposes that they already have every teacher class averages and they should just wo...

Q: A 1975 article in the magazine Science examined the graduate admissions process

A 1975 article in the magazine Science examined the graduate admissions process at Berkeley for evidence of sex discrimination. The table below shows the number of applicants accepted to each of four...

Q: An athletic director proudly states that he has used the average GPAs

An athletic director proudly states that he has used the average GPAs of the university sports teams and is predicting a high graduation rate for the teams. Why is this method unsafe?

Q: Suppose you have fit a linear model to some data and now

Suppose you have fit a linear model to some data and now take a look at the residuals. For each of the following possible residuals plots, tell whether you would try a re-expression and, if so, why....

Q: Suppose you have fit a linear model to some data and now

Suppose you have fit a linear model to some data and now take a look at the residuals. For each of the following possible residuals plots, tell whether you would try a re-expression and, if so, why....