### MATH 251, P&S I, Fall 2011,Wed. Sept. 7, Day 6 Hit reload! .After class, corrected.

Friday Day 7 Quiz (2nd half of class):  In class, closed book:  Stemplot, 5#summary and boxplot.  Mean & s.d. by hand, showing all steps.
Any news on SPSS will go to SPSS info .
Let me (sievers@wells.edu) and Rooz Tavakoli (rtavakoli@wells.edu)  know of computers that SPSS or Morganstore are supposed to work on but don't (name and location of computer, How it doesn't work).

Last HW.  Keep it if you had trouble.We'll discuss it next time, if needed.

SPSS Introduction HANDOUT.  (Links from SPSS info page, Extras outside my door)
Data Files for handout:  on Morganstore: ...\Math251 IPS7e\SPSS for Class.
Also linked here:   Pp.2-5 Studat in SPSS.sav. Same file as it should be after doing p. 2:Studat Completer.sav.  P.7:Studat-as-text.dat     P.6 top: GPS.sav   P.6 mid-bottom: Uscollegestudents.sav
We'll work through as much as we can in class, then you should finish doing or reading Pages 1 thru 5, 7, 8, and 10 top.
Notes
--When opening a file inside SPSS--it may be that clicking on a folder doesn't work; use the Open button (or vice versa).
--It may be that you get no labels on your graphs or tables!  If so, go to the Data Editor,  Variable View, and type in appropriate labels in the Labels column.  Redo your graphs.  (If there are Labels, SPSS uses them to label graphs.  If not, it should revert to using the variable Names, but sometimes doesn't!)

For next time: Back in 121. We'll continue with the Normal distribution, have quiz.

Math 251 Homework Day 6 (Wed., Sept. 7). (all with SPSS)  At least one in by Monday; all Due by Friday, Sept. 16, Day 10.  Hand in each problem as you finish it!  They don't have to be done in order!!  (But they're roughly in order from basicness up.)
Copy numbers from tables, don't print tables.  Print graphs. Printing: bottom p. 1.  Select from the Outline panel what you want, Do Print Preview, then Print.  DON'T print everything!
SOLUTIONS will be posted...

A. Do p.27, 1.44, Table 1.4  (IQ);  Use a histogram and a boxplot. And do p. 48 1.82 a,b. (mean, s, median of IQ) You may find it most efficient to do both together (Hand this one in along with B) (Datasets SEVENTHGRADE and IQGPA are identical.  Use one for both).

B.  Use the data of the problem above (1.44, 1.82, table 1.9 1.4). You found the mean and standard deviation  of IQ there.  Use these values to make a new variable of standardized values of IQ,  z = (x - mean)/sd. (Transform>Compute: Handout p. 8)  What is the standardized value of the first case, IQ = 111? Make a histogram of the standardized values to hand in.  Save the file for yourself, for future use.

C. Still with SEVENTHGRADE and IQGPA,  find for Males and Females separately, the means, s.d.'s, and 5-number summaries of GPA , and show the male and female distributions compared in boxplots (following on 1.43, p.27, where you did stemplots by hand, Day 2).  Discuss how the numerical summaries and the boxplots "go together."  Note in the SPSS dataset the genders are given numerically.  Be sure to label on your output which is which (you can do this by hand, checking with the book, or optionally give the Values column (in Variable view) Labels, Handout p.2 bottom .)

D. Investigate the issue with data wrongly labeled Nominal or Ordinal. Use the file STUDYTIME, from p.26 1.35a (studying time.  You did it for HW by hand): Open the SPSS file and look at Variable View.   Note that  for the "studytim" variable, Measure is (incorrectly) Nominal, but leave it that way.  Using Graphs> Legacy Graphs: Make parallel boxplots and parallel dotplots, to compare M and F study hours.  Examine your plots carefully, and print them to hand in.  Now change the Measure for Studytim to Scale, and re-make the graphs. (The icon in the graph dialog box for Studytim should be a ruler now, not the 3 balls.  If it isn't, hit Reset, so the icon becomes the ruler. Then proceed.)  Print the graphs, compare to the first graphs, and write on your paper what was wrong the first time.
Some procedures just look at the "Type" of the variable (Numeric/String) but the Dot procedure looks at the Measure! and treats Ordinal and Nominal data as if they are just Names, not numbers at all! No telling what a particular procedure will do!!

E. (Do after the previous one) Import the text file STUDYTIME.txt (it's in \Data Sets IPS7e\PC-Text\Chapter 1) (or Mac-Text)
Compare the imported file to the one already in SPSS form.  What do you need to do to make sure it doesn't produce garbage?
Moral:  Check the Measure column in Variable view--for every data set!

F.  Timeplots (Read pp. 20-21)  a) Do pp. 27-8, 1.46 (MARATHON) using a Simple Scatterplot, adding an Interpolation line..  Print your graph and discuss, as in the problem.
b) Now get the data for EARTHDENSITY p.27, 1.42 Make a stemplot or histogram, I don't care which.  Note a little skewness and that it's not exactly  bellshaped--sort of flattish on top. Now make a Timeplot on the order the observations are in the dataset. (I believe these to be the order they were taken in.)  What pattern do you see?  Can this have an effect on the shape of the distribution?

 Sievers home Math251-Fall11/Dayq6.htm 4pm 9/11/11
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