DePaul Least Squares Regression Lines and Graphs Scatter Plots Exam Practice

Question Description

  1. [10 points] Hospital administrators were interested in determining how hospitalization cost (y = cost) is related to length of stay (x = los) in the hospital. The data set “Hospital.sav” (or “hospital.xlsx”) contains the reimbursed hospital costs and associated lengths of stay (the number of days) for a sample of 33 elderly people.
    1. Obtain the least squares regression line for the hospitalization cost as a function of the length of stay, and graph the line on the scatterplot.
    2. Does a linear regression line appear to fit the data well? Explain.
    3. What is the predicted cost for a 7-day stay?
    4. Create the residual plot. It should have the unstandardized predicted values on the x-axis and the unstandardized residuals on the y-axis. What does this plot tell you about the residuals?
    5. Create the normal plot of the residuals. What does this plot tell you about the residuals?
    6. In your opinion, is the obtained linear regression model a good model? Explain in detail.
  2. [10 points] Not all bivariate relationships are linear. When you plot a scatterplot, sometimes you observe a curved relationship. In those cases, we can apply a transformation to the data that will make the relationship approximately linear. [We generally prefer simpler models. And linear regression models are simpler than curved regression models. Also, transforming data is common in statistical practice.]

    One of the most common transformation methods is the log transformation. In this problem, you apply the log transformation to both variables in the data for the previous problem to experiment the model fitness.

    1. Create another variable ‘lnCost‘ (where ‘l’ is an alphabet el) by taking the natural log (ln) of cost. Do the same for the length of stay (los), and create another variable ‘lnLos‘. Then obtain the least squares regression line for ‘lnCost’ as a function of ‘lnLos’, and graph the line on the scatterplot.
    2. Does a linear regression line seem to fit these transformed variables? Better than the one without transformation? Explain.
    3. Create the residual plot of this plot in the same way as the previous problem. How are the residuals different from the previous problem?
    4. Create the normal plot of the residuals. How is this plot different from the one from the previous problem?
    5. In your opinion, is the linear regression model made from the transformed variables a better model? Explain in detail.
Get 20% Discount on This Paper
Pages (550 words)
Approximate price: -

Try it now!

Get 20% Discount on This Paper

We'll send you the first draft for approval by at
Total price:
$0.00

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Services

Ace Writing Center has stood as the world’s leading custom essay writing services providers. Once you enter all the details in the order form under the place order button, the rest is up to us.

Essays

Essay Writing Services

At Ace Writing Center, Nowadays, students normally have extremely busy schedules. You will note that some of them have to take on some evening or weekend jobs in order to get some income that can help them to sustain in college or in the university. This can deny them a chance to write all the essays given. Others usually get bombarded with a lot of work by their lecturers. This can still delay such students from working on all their essays. However, some of them usually try to work on all these essays but end up delivering their work late. This can prevent them from graduating since most lecturers are strict on deadlines. If you want to write a business essay, the wise way is to hire an outstanding essay writing service like us, so that you can get the best results. If you are keen, you will note that many companies usually overcharge their customers. Some of them are there only to make money. And in reality, they really don’t care to build a long term commitment with students. You should not choose such companies. You should take your time and choose a reliable company to work with. Ace Writing Center is the ultimate solution for you. We have been offering our writing service for more than 7 years. This is a clear indication that you will get quality essay writing service. We have a wide range of writers who can work on any business essay that you might have. We believe in doing extensive research so that we can provide quality work to all our clients. .

Admissions

Admission and Business Papers

Have you ever had to write an admission essay for college? The majority of students face the same issues when applying to a university or college and many in such situations decide they need professional help to cope with this matter. They get in a situation when the deadline keeps coming closer but lack motivation to start because they are just not sure if their writing skills are strong enough. We have a solution for you! Ace Writing Center is the best admission essay writing service with a large professional team and years of experience in providing high-quality papers to students of all levels and faculties. The mission of our team is to help students make their dreams of entering a good college come true and that’s what we offer!.

Editing

Editing and Proofreading

Sometimes all the words for your paper just flow out of your mind and into your fingers. You type quickly at your keyboard and there they are, your beautiful words right there on the screen. But you have no idea how to polish it up. You may be wishing there was a paper writing service that offered this type of writing service. Look no more! Here at Ace Writing Center, we offer you an editing and proofreading option that you can't find anywhere else..

Coursework

College Essay Writing

In case you are familiar Ace Writing Center, you know the way to distinguish a better company from a cheap one exactly. First of all, poor service website does not have a sufficient support. We think support team is an essential part of success; it has to answer all clients’ questions and be a connecting link between clients and their writers. On our web-service you will get answers about anything you need and your writer will receive all your instructions, assignments and requirements exactly and swiftly. A writing service that we run has got a flexible pricing system that will save you from senseless wastes and many bonus systems that let you sparing money for something important for you.

See all services