Stat 1000: Tips for Assignment 2
Published: Mon, 09/17/12
Please note that my first midterm exam prep seminar for
Stat 1000 will be on Saturday, Oct. 6, in room 100 St. Paul's College,
from 9 am to 9 pm . I am not ready to take registrations yet,
but I just wanted to give you a heads-up in case you need to make
arrangements to come. I will contact you later on when I am ready to
take registrations.
Did you miss my Tips on How to Do Well in this Course? Click here
Did you miss my Tips on what kind of calculator you should get? Click here
Did you miss my Tips for Assignment 1? Click here
If you are taking the course by classroom lecture (Sections A01, A02, etc.), click here for my tips for your Assignment 2.
Tips for Assignment 2 (Sections A01, A02, etc.)
So far, I have not seen Assignment 2 yet. I would appreciate it if
anyone could send me a copy of the second assignment once it is posted. I suggest, you
click on the link to each question, select and copy the entire question
and paste it into a Word document or the like. Continue to do likewise
for each question, pasting them all into the same Word document.
Perhaps you could put each question on a new page. Finally, save the
document as either a Word file or as a PDF file and attach it to an
email to me. Then I will be able to provide tips to help with the
assignment. Thank you in advance.
Continue to study Lesson 1 in my study book (if you have it) to learn the concepts involved in HW 02.
Ignore any references to Crunchit!.
You are using JMP 10 in this course. The assignment is just an old
assignment that they forgot to update. Use JMP 10 anytime they tell you
to use computer stuff.
When entering numbers into WebAssign, make sure you round off as indicated. Round off, don't trim! For example, if your answer is 2.58 and you are told to round off to one decimal place, you would round that to 2.6, don't just trim off the 8 and say the answer is 2.5. If the next digit is a 5 or higher, you round up.
Question 3 should be done manually. Note, to enter the answers correct to 0.1, they mean round your answers off to one decimal place.
Question 4 should be done manually (i.e. using the Stat Mode in your calculator, not JMP). Be sure to read the Appendix at the back of my book to learn how to use
Stat Mode in your calculator to compute a mean and standard deviation
quickly. By "nearest decimal place", they mean round your answers off
to one decimal place.
Question 5 (the IQ and GPA question):
Click the link to the data file, then select and copy
the entire data set (you can click "Ctrl A" on your keyboard to select
all, then click "Ctrl C" to copy it all). Having opened a "New Data
Table" in JMP, select "Edit" then "Paste with Column Names" to paste the
data in.
Double-click the "iq" column name at top (or highlight and right-click and select "Column Info") and confirm that JMP
has the "Data Type" as "Numeric" and the "Modeling Type" as
"Continuous", changing those settings in the drop-down list if
necessary. Click OK. Do the same for the "gpa" column.
Important:
Double-click the "gender" column (or highlight and right-click and select "Column Info") and make sure that JMP has the "Data
Type" as "Character" (it probably doesn't) and the "Modeling Type" as
"Nominal" (it probably doesn't), changing those settings in the
drop-down list if necessary. Click OK.
Finally, take a look at
the last row of data that has been pasted into JMP. If it just shows a
bunch of dots instead of numbers, click that row to highlight it then
right-click and select "delete rows" to delete that row. Of course, do
not delete any row that has numbers (data) in it!
To find the mean, standard deviation and median in part (a):
Select "Analyze" then "Distribution".
Highlight "iq" in the pop-up menu and click the "Y, Columns" button.
Click OK. You are then taken to a screen that shows a histogram among
other things. You will find the mean and standard deviation in the
"Summary Statistics" section and the median in the "Quantiles" section. Type the correct values in the boxes provided in WebAssign
To make the boxplots and histogram in part (b): In the toolbar
at the top of your data spreadsheet, select "Analyze" then
"Distribution". Select the "gpa" column and click the "Y, Columns"
button. Click OK. Your histogram appears sideways but they didn't ask
you to switch it horizontally, so don't bother. If they want to see it
the typical way (and they will request that if they want it), click the
red triangle next to your variable above the histogram and select
Histogram Options from the drop-down menu. Select "Vertical".
They request the count on your histogram, so click the red triangle next to "gpa" and select "Histogram Options" and select "Count Axis".
Click the red triangle next to "gpa" and select "Quantile Boxplot" (if
it isn't checked already) and "Qutlier Boxplot" as well to get the
desired boxplots. Click the blue triangles next to "Quantiles" and
"Summary Statistics" to hide that stuff.
You will need to copy and paste this output into a document to get ready to add the output from part (c) as well. Here is how to do that:
Click the thin blue line near the top of the window that has the histogram, etc. to reveal the toolbar. Select the icon that looks like a fat white cross or plus sign "+". This is your "Selection" tool. Your mouse cursor should now have changed from an arrow to that white cross. Click the title bar that says "Distributions" at the top of the output and that should select the entire output (histogram, boxplots, etc.). Right-click and select Copy.
Now, open whatever program you use for word processing (such as Word). In a new document, right-click and select Paste to paste your output into the document.
They also ask you to comment on the graphs. I suggest you do this by adding a note to the document you have just pasted the output into. Just type your comments below all the JMP stuff. When they say "comment on what feature of the data explains the difference between the median and the median," they are implying they are different. What is the shape of your distribution and what does that mean about the mean compared to the median?
Leave this document open, as you will need to paste the stuff from part (c) into it as well.
To make the side-by-side boxplots in part (c): Back in your data spreadsheet, select "Analyze" then "Fit Y By X".
Highlight "gpa" and click "Y, Response". Highlight "gender" and click
"X, Factor". Click OK. This should open a pop-up window with a bunch of dots arranged vertically on a graph for Males "1" and Females "2". If that does not happen, you probably did not follow my instructions above to make sure the "gender" column is Character and Nominal. In that case, close the window and make the appropriate adjustments in your data table.
Now click the red triangle and select "Display
Options" (down near the bottom of the menu), then select "Box Plots" to get your side-by-side boxplots.
Click the thin blue line near the top of the window that has
the side-by-side boxplots, etc. to reveal the toolbar. Select the icon that looks
like a fat white cross or plus sign "+". This is your "Selection"
tool. Your mouse cursor should now have changed from an arrow to that
white cross. Click the title bar that says "Oneway Analysis of ..." at the top
of the output and that should select the entire output (graphs etc.). Right-click and select Copy.
Return to the document you already opened in part (b). Make sure you are below the stuff you already have in the document. Perhaps you should go to the end of what you have pasted and written for part (b), and type CTRL-Enter (hold down the "CTRL" or control key while also pressing the "Enter" key) to create a new page in the document. Right-click and select Paste to paste the JMP stuff for part (c).
They also ask you to compare the boxplots. Again, just write your comparison in your document below the JMP output you just pasted in. Compare the shape, centre and spread.
You are now ready to save and upload the file that answers part (b) and (c). In your Word document (or whatever program you are using), select "File" then "Save As" and select "PDF File". Type in whatever name you want the file to have in the "File name" section. Select which folder you want to save the
file in (I suggest you select "Desktop" so that the file will just
appear write on your desktop home screen. Click
"Save" or "Publish". You should now have your file ready to upload into the
assignment.
Question 6 should be done manually. Read my section in Lesson 1 on "The Effect of Changing Units on Centre
and Spread" to properly prepare for this question and look at my questions 17 and 18 for examples.