Stat 2000: Assignment 5 Tips (Classroom Lecture Sections)
Published: Wed, 04/03/13
My tips for Assignment 5 are coming below, but first a couple of announcements.
Please note that my final exam seminar for
Stat 2000 is now scheduled and I am taking registrations. I have split the seminar into two days since we will have to cover Lesson 6 in
Volume 1 as well as all of Volume 2. The seminar is from 9:00 am
to 6:00 pm each day in room 100 St. Paul's College. Each day will cost $40 or, if you attend Day One,
you can attend Day Two for half-price (you will pay a total of $60, in
other words).
Day One is Easter Sunday, March 31 and Day Two 2
weeks later on Sunday, April 14.
Did you miss Day One of the seminar? I have a special offer on my
audio podcasts for students who attend at least one of Day One or Day
Two of the seminar. Of course the audio is available to purchase even
if you do not attend the seminar at all. Click here for more info:
Make sure you do: Tips on How to Do Well in Stat 2000
Did you read my Tips on what kind of calculator you should get?
Did you miss my Tips for Assignment 4?
Tips for Assignment 5 (Classroom Lecture Sections A01, A02, A03, etc.)
Don't have my book? You can download a free sample containing Lesson 3 at my website here:
You need to study the Chi-Square Goodness of Fit part of Lesson 8: Chi-Square Tests (if you are using an older edition of my book, this may be Lesson 9). You also will need to study Lesson 9: Review of Linear Regression and Lesson 10: Inferences for Linear Regression
(up to the end of question 3, you do not need to study the Multiple
Linear Regression section at this time). Note that they have omitted
Multiple Linear Regression and Lesson 11: Nonparametric Tests (The Sign
Test) this term.
Question 1 is not unlike my question 5 in Lesson
8. Make sure you follow their instructions for rounding. They make
their goodness-of-fit table horizontally, while I prefer to make mine
vertically.
Question 2 is not unlike my question 8 in Lesson 8.
Question 3 is not unlike my question 11 in Lesson 8.
Question 4 is a runthrough of Linear Regression.
Be sure to study Lessons 9 and 10 in my book before attempting this and
the rest of the questions in this assignment. You should especially
work through question 1 in Lesson 9 and questions 1 and 3 in Lesson 10.
Note that they give you SSE, the sum of the squared residuals, so
you are able to compute the variance of the residuals (MSE = SSE/DFE).
MSE is your estimate for σ, as requested in part (e). That is what I call se, the standard deviation of the residuals, the estimate for σε, the standard deviation of the population of residuals.
Never forget, in a regression context, if they start talking about σ or s, they are referring to the standard deviation of the residuals for the population or sample, respectively. To add to the confusion, they called s, σ-hat in this part.
To do Linear Regression in JMP:
Open a "New Data Table". Enter all the data for x in Column 1 and
all the data for y in Column 2. Be sure to name the columns
appropriately. I think you all get different questions here, so I am
unable to be more specific. Select "Analyze, Fit Y By X".
Highlight "Column 1" and click "X, Factor". Highlight "Column 2" and
click "Y,
Response". Click OK.
You should now be looking at a scatterplot. Click the red triangle and select Density Ellipse and select 0.99 (it doesn't matter; you don't want this at all, but this gives you a summary of the means, standard deviations, and the correlation coefficient, r). Click the red triangle that appears below the scatterplot which says Bivariate Normal Ellipse and deselect "Line of Fit" to make the ellipse disappear from your scatterplot. You will also note that there is a title bar called Correlation below the scatterplot now. Click the blue triangle to open it up and confirm the means and standard deviations match those you were given. If not, perhaps you were mixed up which one was x and which one was y?
Click the red
triangle
and select "Fit Line" to get the least-squares regression line. You
now have all the outputs you need. Be sure to
read in Lesson 10 the connection between the t test statistic for the
slope and the t test statistic for the correlation. And also the
connection between t for the slope and F for the slope. Although they
want
you to do a lot of this question by hand (and you certainly should since
that will also happen on the exam), do note that JMP does do a lot of
this stuff for you and you can use it to check your answers before you
submit them.
Question 5 is not unlike my question 2 in Lesson 10.
Question 6 is not unlike my question 3 in Lesson 10. Note that the proportion they ask for in part (c)
is just the decimal version for the relevant percentage. As I show
in my question 3, you can use the ANOVA to find that percentage or
proportion.
Question 7 is probably the hardest question I have ever seen in a statistics assignment.