JMP commands for Exercise 1.80 (p. 72)

The first step is to install the data that comes with the text, or download the files for the homework from the class Homework webpage. In what follows I'll assume you have the data on your hard-drive somewhere.

• There are four data formats available on the class webpage. I'll go through what to do with three of them here.

  1.

  JMP 4.0 format: If this works for you then it's the easiest way to go. After starting JMP you should see a dialog labelled JMPIN Starter. From here you can choose Open Data Table. Use the Open Data File dialog to search for your file. Mine is in C: $\backslash$Stat301 $\backslash$ex01-80.JMP (you won't see the .JMP). Double click the file name or the JMP icon to open the file into a spreadsheet.

  2.

  The JMP format will only work for you if you are using version 4.0 of the software. There may be other issues such as computer operating system too that I'm not aware of. There is a portable format known as SAS Transport format that can be read by JMP. For me the file is C: $\backslash$Stat301 $\backslash$ex01-80.XPT. Start with Open Data Table from the JMPIN Starter dialog again to find this file on your system. Double clicking the file name or the icon beside it should open the file.

  3.

  If neither of the above formats work, you can import the data from the plain text file. For JMP v.4 again start with the JMPIN Starter and choose Open Data Table. Now you'll have to go to the ``Files of type:'' part of the dialog and scroll to ``Text Import Files''. You should now see the file ex01-80.TXT displayed without the .TXT extension. Double click to open.

• THIS ITEM IS FOR USERS OF OLDER VERSIONS OF JMP: (but the instructions on how to change the type of a variable in your dataset are useful for everyone ...) If you are using an earlier version of JMP, you should read in the data from the ascii format file. In JMP version 3.x start up the software an under the File menu select Import $\rightarrow$Text/Others and choose the location and file name. Note that if JMP can not find a file that you know to be in a certain directory, try searching for files of type: All Files, rather than just Text Files.

  JMP tries to be helpful and assigns a data type to each column in your dataset. Unfortunately when it reads in the data from the .TXT file the first row contains the variable names. JMP then thinks you have Nominal (non-numeric) data. It is for this reason that I've made available a version of the plain text file without the column label. You should use this version if you are accessing the data sets from the web. If not, and you would like to use the data from the data CD, you'll have to label the column yourself, delete the first row of the spreadsheet and then change the variable type.

  • To give a column a name, double-click on Column 1. Now you can hit the delete key and enter the variable name. In the case of column 1 enter SURVIVAL.
  • Click on the 1 in the first row to highlight this row. Now you can use Rows $\rightarrow$Delete Rows to delete the row.
  • To change the data type and modelling type of a column, single-click the column header and go to Cols $\rightarrow$Column Info. You'll see a description of the column. We'd like to change the data type to Numeric and the modeling type to Continuous. Use the menus to do so and click OK when done.
• Now might be a good time to save your work. Under the File menu choose Save As to save it as a JMP format file.

• We're finally ready to do some summary statistics.
  • Under Analyze choose Distribution (or Distribution of Y in older versions of JMP) to get univariate summary statistics.
  • Click a variable name to highlight it and then click Y,columns (or the >>Add>> button in older versions) to add it to the list of variables we'd like summary statistics for.
  • Click OK to see the results.
  • To change the layout of the histogram, right-click on the button with the variable name on it (SurvivaTime or SURVIVAL depending on how you read in the data). Now go to Display Options $\rightarrow$Horizontal Layout and click. For earlier versions of JMP, instead of right-clicking on the button with the variable name on it, find the check-mark button on the lower-left corner of the Distribution window and click there. Choose Horizontal Layout.