Math 151 , Fall 2005, Day 12 Wed. Sept. 21 Hit reload...  After class

--Exam 1  Next time: Friday Sept 23, Day 13, in class, closed book.   Bring a simple calculator. I will give you copies of the Normal table.  You may stay late into the lunch hour if you like. If you will need extra time, and can't stay into the lunch hour, make arrangements with me by this afternoon, please.
Covers Part I:through p.112 !!!Including!!!Yes !!!: "backward" normal problems with raw data like p.90..Percentiles II, p. 92-3 questions 2,3.  You will need to read SPSS output, but not tell how to produce any. You will need to calculate "by hand" a standard deviation for four numbers. (As well as medians, quartiles, etc.)   Problems like HW + some true-false or multiple choice types.
 Sample exam was given out, solutions outside my door, & on reserve.
I (SRS) will be in my office this afternoon till 4; Fay is holding a help session Thursday evening--" in the Math Lab beginning at 8pm going no later than 10pm.  I will stay only as long as there are questions.  Please show up on time.  If you cannot make it at 8 but would still like to come please email me (fnielsen) and I will stick around for you.  "
HW Day12 (Wed. Sept. 21):
Reading   D&V Ch7 Scatterplots, first thru 117 (AS7-1&2), then Correlation, the rest. (AS7-3&4) You do not have to be able to calculate r by hand.  You should be able to guess roughly at an r for a swarm of data.
Hand in Monday . (From D&V unless otherwise noted) 
Scatterplots
p. 130, 5,6 describing simple plots
 1,4 what relationship ALSO sketch an appropriate scatterplot for each. 
  8 Derby (This is actually a timeplot)ALSO, how does the variability  change over the decades? 
 9 Pottery For a, dotplot is ok instead of histo.  ALSO, is Batch # really Quantitative, or Ordinal? 

Postpone the rest; will be part of Day 14 (Monday) HW (Feel free to start it if you want.)
SPSS Handout: Repeat the work of page 1, and do problems 1-5 on p. 3.  Keep this work and hand it all in when all problems have been assigned. 

HW in Activstats for SPSS (Disks are on reserve in Long; I'll lend one if I'm here):  Go to Chapter 7, use the menu button with the House icon.  Scroll thru the problem list to find the ones given.  In each problem involving data, a button will allow you to launch SPSS and open the correct file.  Then save the file for yourself, do the analysis. 
MRA-81-4 (SPSS) Metabolic Rates, M/F 
MRA-83-8 (SPSS) Ed. Spending vs. Teacher Salaries 
MRA-80-2 (SPSS)  Speed vs. Fuel Consumption (describe) 
TRE-58-26 (SPSS)  Bear neck/weight  ALSO Make a plot with the M&F bears marked differently.  What if any sex differences do you see here? 

MRA-95-13 (SPSS, and pencil) Corn plants.  This is a first introduction to the idea of predicting or estimating a "typical" y for a given x value.  Ch. 8 will do an important special case of that.
- - - - - - - - - - - - - - - - - 
Correlation (beginning):
SPSS Handout: Do problem 6, p. 3.  Keep this with the previous work. 
p. 130 #11, 12  Match # to scatter.  (Use handout of typical ones, AS7-3 Activity 2) 
ActivStats: MRA-89-4 (SPSS) Speed vs. Fuel Consumption (cf. MRA-80-2) r~0, why?

Read, 
 to discuss 
Optional 
Questions for Exam??

Relationships:(D&V Ch 7 thru p.117, AS7-1&2  )
Handout on SPSS Scatterplots etc. (D&V Ch. 7-10, AS 7,8,9)  pp.1-3, p.4
govsal_vs_pay.sav  is the file used for most of the handout. (In SPSS for Class 05 folder)

    Did 2 categorical variables (2-way tables), quantitative vs. categorical (side-by-side boxplots, stemplots, histo's)
Relating 2 quantitative variables:  Scatterplots
  explanatory = predictor = independent = "x" = horizontal axis ( = "cause", only sometimes!)
                       response =    dependent   = "y" =  vertical axis      = ("effect ")

(Living histograms:  Height vs. weight, Height vs. gpa)
Timeplot (p.43-4) is special case, "time" on x axis.

Discussing Scatterplot :
Unusual features?   Clusters (analyze each separately)?     Outliers? (label if possible; who?, why?)
For simple cloud, line, or curve:
Form (linear, curved, ...?)
    Strength of relationship (how un-scattered)  "Weak, moderate, strong"
Direction
    Positively associated:  y increases as x increases (generally).
    Negatively associated:  y decreases as x increases.
Start here Monday
Mark subgroups differently to do comparisons. (Subgroups defined by categorical variable, like Sex, Region of country)
  Some scatterplot data:  educ-v-mortality.sav  ,   studatsp03.sav
Handout on SPSS Scatterplots etc. (D&V Ch. 7-10, AS 7,8,9)
govsal_vs_pay.sav  is the file used for most of the handout. (In SPSS for Class 05 folder)



Correlation (D&V Ch.7 pp118ff, AS7-3&4) -- a number measuring strength of straight line ("linear") relationship.
Website,  http://www.whfreeman.com/scc,
ClickNetscape toolbars to minimize them, if needed.
  Choose "Statistical Applets",  Correlation/Regression.  Play with data points, observing the Correlation Coefficient.
    Check in the "Show Mean X &Mean Y lines" box.  See how much is in each quadrant.


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