Stat 1000: Tips for Web Assign HW 03
Published: Tue, 02/01/11
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Tips for Web Assign HW 03
When working with Web Assign, always enter the answer to one specific box and then click "Submit Answer" to confirm that is correct before you move on to another box. Do not enter several answers all at once in several boxes before you click "Submit Answer". You risk being marked wrong due to some typo or something.
For some strange reason, JMP 8 occasionally computes wrong answers even if you have copied and pasted your data correctly. I suggest that, if it is feasible, type the given data into your calculator (in Stat mode as shown in Appendix D of my book), and have your calculator compute the sample mean. Compare that answer with JMP's answer for the sample mean. If they are the same, everything is fine. If they are not the same, close JMP 8 and restart it, recopy and paste the data, and check again. Sometimes you have to do this 2 or 3 times before JMP finally works. If it is not feasible to use your calculator to compute the sample mean, have JMP do the question 2 or 3 times, being sure to restart JMP and recopy the data each time, and confirm that JMP gives you the same answer each time before risking entering the results into Web Assign.
For the JMP 8 part of the assignment, here are some tips:
Once you have installed JMP 8 and opened it, you are shown a menu with various buttons to click. You will almost always click "New Data Table" to enter new data. In the rare event they have given you a JMP file with the data already entered in it, you will simply open that file which would probably already open JMP for you. If you happen to enter data in yourself and save the file (a good idea), you can select "Open Data Table" to open up the saved file.
To copy and paste data into JMP: First, of course, select and copy the given data set. Now, open JMP and click "New Data Table". In the toolbar at top select "Edit" then "Paste with Column Names". That pastes all the data in and names the column appropriately.
Note, you must save your document as a PDF file to upload it into Web Assign (no other format will be accepted). If you don't know how to do this for the software you are using try the help files or Google "save as pdf file" for some helpful steps or programs that enable you to save documents that way for free. MS Word 2007 is capable of saving as pdf. If you are using a different program and do not have a "save as pdf" option, download the "pdf writer" they give you in Web Assign or Stats Portal. If you are unable to "save as pdf", try selecting "print" as though you were going to print your file, then select your "pdf printer" rather than your physical printer in the print options. That will then save your file in pdf form.
If you are taking the course by distance/online (Section D01) click here to see your tips for HW 03.
Study Lesson 4 in my book, if you have it, to prepare for this assignment.
Thankfully, there is no JMP needed for this stuff.
Question 4
The diagram they want is the arrow charts I draw in question 7 of my Lesson 4. For those of you who are using Web Assign and have to draw one of those arrow charts and upload it, there are many ways to do it and it depends on how fancy you want to get and what program you are using. A pretty simple way might be to insert a table into your document (In Word, select Insert, and choose Table) and give yourself lots of rows and columns to work with (I'd say at least 4 columns and 5 rows; you can always add extra rows if you need them by just pressing the Tab button when your curser is in the last cell of the last row). Type in the various words you want in the approximate positions throughout the table. To connect words together with arrows insert arrows (in Word, select Insert, Shape, and select the Arrow). You then use your mouse to click where you want the arrow to start and where you want it to stop. Get rid of the lines on your table by right-clicking your mouse while pointing anywhere in the table and selecting Table Properties. Then, select Borders and Shading and select None. Don't get rid of the lines until you have made your whole chart since the lines will help you place your words throughout.
By the way, I show you how to make a table in question 7 to identify the treatments needed for a two-factor experiment. When you have a three-factor experiment, make a table for just two of the factors first, then, give all of those treatments to the first level of the third factor. You then give those exact same treatments to the second level of the third factor, and so, until you have used all the levels of the third factor.
Study Lesson 2 in my study book (if you have it) to learn the concepts involved in HW 03.
Ignore any references to JMP 6SE or Crunchit!. You are using JMP 8 in this course. The assignment is just an old assignment that they forgot to update. Use JMP 8 anytime they tell you to use computer stuff.
Questions 1 and 2 are just like my questions 5 and 6 in Lesson 2. Note, a "cumulative proportion" is a left area on the bell curve. Put another way, cumulative proportion is P(Z < z).
Question 3 is a good run through of X-bell curve problems that I teach in the latter half of Lesson 2.
For the JMP 8 part of the assignment, here are some tips:
Open a "New Data Table" in JMP. To copy and paste the data into JMP, in the toolbar at top select "Edit" then "Paste with Column Names". Double-click the "gpa" column heading and make sure the Data Type is Numeric and the Modeling Type is Continuous, using the drop-down menus to fix that if necessary. Double-click the "sex" column heading and make sure the Data Type is Character and the Modeling Type is Nominal, using the drop-down menus to fix that if necessary. Click OK.
To get side-by-side boxplots: In the toolbar at the top, select Analyze then select Fit Y By X. In the pop-up menu, highlight the gpa column and click the "Y, Response" button. Highlight the sex column and click the "X, Factor" button. Click OK. You will then see a graph with a vertical array of dots for the males (1) and the females (2). Click the red triangle next to "Oneway Analysis ..." and select "Display Options". You will then be able to select "Box Plots" in the Display Options sub-menu.
To get normal quantile plots: They want you to make a normal quantile plot for the males and a separate plot for the females. In the toolbar at the top, select "Analyze" , then "Distribution". In the pop-up menu, highlight "gpa" and click "Y, Column". Highlight "sex" and click "By". Click OK. You now see separate histograms for the males and for the females. Click the red triangle next to "gpa" for both the males and for the females, and select "Normal Quantile Plot" to get a separate normal quantile plot for the males and females.
A normal quantile plot checks to see if a sample's distribution appears to be normal. If the data follows a normal distribution, the normal quantile plot will look like a rising diagonal line. If the plot looks curved rather than linear, there is evidence the data is not normal. However, none of that seems to matter in your question, all they ask is which students are clear outliers, which, personally, I think is much easier to see from your side-by-side boxplots than from your normal quantile plots.