MATH 251, Probability and Statistics I, Fall 2001, Oct. 15, Day 19

Sec 3.3, cont.
Pooling data:  phat, xbar.
Results = part of Sampling distributions of the statistics which are used to estimate   the parameters p and mu.

Ch. 4, Sec. 4.1
Random phenomenon= Chance mechanism. Any individual outcome is uncertain, BUT in a large number of repetitions, a regular distribution of outcomes occurs.
Variability happens.  In the long run it settles down.

Probability of any outcome of a random phenomenon:  proportion of times it would occur in a very long series of  independent repetitions of the experiment.  Long-term relative frequency.
(This is the "frequentist" interpretation. Mainstream)

Day19  Reread 3.4, sampling distributions, if necessary.  Read 4.1 and ahead, 4.2.
Hand in: For 4.1. 
4.1, penny spinning.
4.6, poker
A: At the computer: Before starting, open a new document in Word (or another wordprocessing package). Type your name and a bunch of "enter" keystrokes.
Go to the text website, http://www.whfreeman.com/ips/
Scroll down, choose Statistical Applets, and choose "What is Probability?"  Pick some probability between .1 and .9, and simulate tossing coins with that probability.  Watch it vary and settle down. Pause after 30 or 40 tosses.  Capture the image and paste it to your document.**   Go back to the probability simulation.  Keep tossing till you reach 500, the maximum for the program.  (You can set it to toss up to 40 at a time.)  Capture this image and paste it also to your document.  Arrange them one under the other, and print it to hand in (If using an inkjet printer, the economy fast mode is sufficient. This is not great art.)  
Graph 4.1 p.291 is like this exercise only the #-of-trials (horizontal) scale is done on a log scale.
Read the rest of the problems in section 4.1 and understand what you would do if they were assigned. 
(SPSS is not easy to produce multiple trials from, so we won't) 
Read, discuss  Optional
**To capture the image of the active window  in Microsoft:  On the keyboard, hold down the Alt key and  tap the PrintScreen key (Gray, usually upper right somewhere).  This puts it on the Clipboard.  Go into the document and do Edit>Paste.  The image should be a picture in your document.  (I don't remember how on the Macintosh; I do know there's a way...)


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