Stat 1000: Tips for Assignment 1

Published: Sat, 01/14/12

 
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If you are taking the course by Distance/Online (Sections D01, D02, etc.), click here for my tips for your Assignment 1.
 
If you are taking the course by classroom lecture (Sections A01, A02, etc.), click here for my tips for your Assignment 1.
 
Tips for Assignment 1 (Sections A01, A02, etc.)
 
Study Lesson 1 in my study book (if you have it) to learn the concepts involved in Assignment 1.
 
Questions 1, 2 and 3, of course are dealing with "types of variables" and the graphs you would draw to illustrate them.
 
In Question 4, note that a percentile is what percent of the data is below that score.  So, for example, the first quartile could be described as the 25th percentile; the second quartile is the 50th percentile; and, the third quartile is the 75th percentile.
 
Never use JMP to answer a question unless they specifically tell you to.  Whenever they do tell you to use JMP, never go out of your way to click red triangles to add things to the graph (like put titles on histograms, or label axes).  Whatever JMP gives by default is all they require unless they specifically request you add something to the output or remove something from it.  Of course, I will always give you specific steps to add/remove anything they do require.
 
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 enter data into JMP manually: Click "New Data Table" and you are automatically taken to an empty spreadsheet with one column. If you ever need two or more columns, simply double-click the space to the right of "Column 1" to create "Column 2". You can repeat this to create "Column 3", etc. You can then type in the data, using "enter" or "tab" or your arrow buttons on your keyboard to move from one cell to the next.
 
To make a histogram in JMP: First, type in the data as I describe below for making the side-by-side boxplots (you may as well do it that way now, so that you don't have to do the JMP stuff twice).  Now, in the toolbar at the top, select "Analyze", then select "Distribution".  (You could also just click the icon on the toolbar that looks like a sideways histogram.)  In the pop-up menu that appears, click "weight" in the "Select Columns" section to highlight it, then click the "Y, Columns" button.  Then click "Sex" in the "Select Columns" section to highlight it and click the "By" button.  Now click OK and you will be taken to a screen that shows histograms for both Females and Males weights.  It is the Females histogram they want.  (If you only typed in the Female weights into the spreadsheet at this time, you don't have to do the "By" part above since JMP doesn't know there are both Female and Male weights yet.  If you have typed in both the Female and Male weights, as you have to do for the side-by-side boxplots below, then you must follow the steps I outline to get your histogram.)
 
If you want to rotate your JMP histogram 90 degrees so that it looks better (you don't have to do this since they don't ask you to), click the red triangle next to "weight" above the Female histogram and select "Histogram Options" and then "Horizontal Layout".  I also recommend that, for this problem, you select "Histogram Options" and then "Prob Axis".  That then labels the proportions (or relative frequencies) on the axis, which may assist you in answering part (b) of the question.
 
Double-click the column heading for each quantitative variable in your table and make sure the Data Type is Numeric and the Modeling Type is Continuous, using the drop-down menus to fix that if necessary. Click OK.
 
To make the side-by-side boxplots in question 4: Open JMP and select "New Data Table".  Double-click "Column 1" and name it "weight" and click OK.  Now type all the weights of Females down that column and continue to type all the weights of Males down that column as well.  That means you will end up with 108 rows when you are done.
 
Double-click the region on the spreadsheet just to the right of this first column name to create a second column, and name that column "Sex".  Now you can type in the relevant information in each column, using your "Tab" key or the arrow buttons on your keyboard to move from one cell to the next.  Since you are typing in the words "Female" and "Male" alot, you may want to copy the word and paste it into all the relevant cells (it is very important that the word is spelled exactly the same each time; a misspelling will screw everything up).  You will end up typing "Female" 54 times down the second column, and the "Male" 54 times.
 
JMP should have recognized the data after you typed it in, but just to be sure, once you have all the data typed in, double-click the "Sex" column at the top and confirm that the pop-up menu says the Data Type is "Character" and the Modeling Type is "Nominal", changing it to that if necessary.  Also double-click the "weight" column and confirm in its pop-up menu that the Data Type is "Numeric" and the Modeling Type is "Continuous" making any necessary adjustments.
 
Now, select "Analyze" then "Fit Y By X". Highlight "weight" and click "Y, Response". Highlight "Sex" and click "X, Factor". Click OK. Now click the red triangle and select "Display Options", then select "Box Plots" to get your side-by-side boxplots.  Select "Display Options" again, then deselect "Points" and repeat and deselect "Grand Mean" to remove these things grom the graph as they request.
 
You can now print this graph and answer their questions.
To make a Time Series (Question 5): Select Analyze in the toolbar, then select Modeling in the drop-down list and finally select time series. Select your "Year" and click X, Time ID and select "Homes Cleaned" and click Y, Time Series. Click OK. Just ignore that other pop-up menu asking about time lags or autocorrelations or whatever, click OK and move on. None of that has anything to do with the time series.
 
To get rid of any outputs you don't want to print, click the red triangle and deselect the unwanted things. (Never get rid of anything on a JMP printout unless they tell you to.)
 
In question 6, although they don't make it clear, I think you are expected to work out the mean and standard deviation by hand as I show in my question 6 of Lesson 1.  Be sure that you also compute these with your calculator's Stat mode as I show in the Appendix of my book as a check.  Note that part b is using the concept of "The Effect of Changing Units on Centre and Spread" that I discuss in Lesson 1.
 
Tips for Assignment 1 (Distance/Online Sections D01, D02, etc.)
 
Study Lesson 1 in my study book (if you have it) to learn the concepts involved in Assignment 1.  This lesson will also set you up for Assignment 2.
 
Never use JMP to answer a question unless they specifically tell you to.  Whenever they do tell you to use JMP, never go out of your way to click red triangles to add things to the graph (like put titles on histograms, or label axes).  Whatever JMP gives by default is all they require unless they specifically request you add something to the output or remove something from it.  Of course, I will always give you specific steps to add/remove anything they do require.
 
Anytime a question wants you to "fill in the blanks" with key vocabulary terms, go to the appropriate section of your textbook (remember you have an online version of the textbook in Stats Portal if you selected the electronic option on your book list), and you will find the exact sentence they are giving you with the obvious word they want you to type in.
 
The question asking you what graphs to use is really asking you is the data "quantitative" or "categorical".  If you are collecting two sets of quantiative data, then you would use a back-to-back stemplot or side-by-side boxplot to compare them (and no other graphs).  If you are collecting quantitative data as time goes by, you would use a time series or timeplot and nothing else. 
 
To type in the split stemplot they request, use the vertical line on your computer keyboard to separate the stem from the leaves ("SHIFT \" will give you " | ").  Don't worry if your columns don't end up perfectly lined up, just do the best you can.  Be sure to label the first line in your stemplot "Stem | Leaf", then enter all the stems and leaves row-by-row underneath.
 
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.
 
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.
 
Double-click the column heading for each quantitative variable in your table and make sure the Data Type is Numeric and the Modeling Type is Continuous, using the drop-down menus to fix that if necessary.  Click OK.
 
To make a histogram: In the toolbar at the top, select Analyze then select Distribution.  Select the column you want the histogram for ("tuition" in this case) and click the Y, Columns button.  Click OK.  Your histogram appears sideways.  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 Horizontal Layout.
 
For the pole-vault question: You will have to enter the data manually into JMP.  Click "New Data Table" to enter new data.
 
To enter data into JMP manually: Click "New Data Table" and you are automatically taken to an empty spreadsheet with one column.  If you ever need two or more columns, simply double-click the space to the right of "Column 1" to create "Column 2".  You can repeat this to create "Column 3", etc.  You can then type in the data, using "enter" or "tab" or your arrow buttons on your keyboard to move from one cell to the next.
 
In this particular pole-vault question, double-click "Column 1" and name it "Year".  Click OK.  Double-click the space to the right of Column 1 to create Column 2.  Name that column "Height".  Type in the data you have been given.
 
To make a Time Series: Select Analyze in the toolbar, then select Modeling in the drop-down list and finally select time series.  Select your time variable and click X, Time ID and select your variable you are tracking and click Y, Time Series.  Click OK.  Just ignore that other pop-up menu asking about time lags or autocorrelations or whatever, click OK and move on.  None of that has anything to do with the time series.
 
To get rid of any outputs you don't want to copy and paste, click the red triangle and deselect the unwanted things.
 
To copy and paste the parts you do want, select the icon on the JMP toolbar that looks like a fat white plus sign "+" (the Selection tool).  You can then click various parts of the printout to select the sections you want.  Copy and paste into Word or something like that.
 
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, Google "pdf995 download" for a free program that can be used to save documents in a pdf format.  Note that, if you are using a program like this, often it loads a "pdf printer" onto your computer.  Then, to save your file as pdf, you actually select "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.