Math 263 Fall 2011
Introduction to Statistics and Biostatistics
Announcements

Review Session for the Final Exam:
 Location: Math 501
 Date: Tuesday, December 13, 2011
 Time: from 5pm to 6:30pm.
 Here is a new final info. It has a link to Chapter 9 and 12 practice problems.
 Rules of newly announced extra credit are here.
 An updated list of R resources is at the bottom of the page, including tutorials and refcards ("cheat sheets").

You will find Chapter 9 materials here. There is a PDF file showing stepbystep how to conduct a chisquare test. Also, there are R examples (in the R subfolder) which contain real scripts I used to solve some of the Chapter 9 WebAssign problems. You will also find the output I generated today by running R in class. If you use Excel for solving Chapter 9 WebAssign homework, you can still benefit by using the outer product operator (%o%) which you can call from R commander after you move some data to R.
You may use "Put R variable" this time to transfer data to R; if you transfer data using "Put R data frame", make sure to include table headings in the transfer, so that data have names, say "x" and "y". If the frame is called "aframe", you can access individual columns by using variable names "aframe$x", "aframe$y". Alternatively, you can use
attach(frame)
after which R makes the variables named "x" and "y", which stand for the columns of the data frame.  Excel/R Assignment 6 is now available here.
 Excel/R (this time pure R!) Assignment 5 is now available here.
 There is a big practice test (over 50 problems) for Midterm 3 and the Final Exam. The answers to the practice test WILL NOT be posted.
Links to general resources
 Syllabus, including course policies
 Calendar
 WebAssign
 PowerPoint Lecture Notes: 6e  7e
 Student Resource CD
 Another Math 263 site
 Rules of grading multiple choice questions
Clicker Quiz Results
Excel Assignments
Assignment 1  due September 7
Assignment 2  due September 21
Assignment 2.5  due September 26
Please refer to Assignment #2 for the dataset. Instructions (Word 2007, with embedded Excel example)
 Instructions (Word 2003, only text, no embedded Excel due to incompatibility)
 Instructions (PDF, no "live" excel objects)
 Original instructions and an Excel example at another website.
Assignment 3  due October 24
Please refer to Assignment #2 for the dataset.Assignment 4  due November 14
Assignment 5  due December 9
Assignment 6  due December 9
Data sources
Video Tutorials I recorded (for Windows Media Player)
Links following the material discussed in class
 The definitive guide on how to calculate the fivenumber summary by hand
 How to make a fivenumber summary with R?
 A detailed definition of a Quartile
 There is not a single way to find quartiles! See this insightful discussion
 Interquartile range (IQR)

Wikipedia's
skewness of distribution article. Note:
leftskew (rightskew) means left tail is longer than the left
(right). Also leftskew = negative skew and rightskew = positive
skew, using another terminology.
 Download R from here

Download RExcel from here
 RExcel Video
 RExcel Wikipedia page
 A local copy of RAndFriendsSetup.exe. May be outdated! Use only if you cannot obtain a copy from the distribution server in Austria. Disclaimer: I do not take any responsibility for the functioning of this thirdparty file, or the possibility that it may contain malware.
 A third party installation instructions. Disclaimer: I do not know if these work, and I do not take responsibility for their content, or possible malware on this website.
 Midterm 1 Information  now updated for Fall 2011
 PDF files explaining how to do linear regression with R
 A page explaining how to do linear regression with Excel
 Local SimpleR resources
 Wikipedia article on the sum of squares and coefficient of determination
 Class notes on regression and sum of squares
 2011 lecture notes example (by hand)
 Exact linear relationship example (PDF)
 NonExact linear relationship example. Contains an R regression calculation example, and a full calculation of the sums of squares (PDF).
Chapter 3 Links
 Experimental Unit discussion
 Statistical unit definition on Wikipedia
Midterm 2
Chapter 6
Notes related to Chapter 6 are here:Chapter 7
Notes related to Chapter 7 are here:Midterm 3
 Midterm 3 Information  updated for Fall 2011
Chapter 7  the twosample ttest
 Wikipedia article on the Welch's test with the WelchSatterthwaite formula for the number of degrees of freedom. Note that this is the test described in the book and implemented by the R function t.test, for the situation when sample sizes are uneven and we have no reason to believe that the two populations have identical variances.
 An excellent Wikipedia summary of several variants of the ttest used for a number of distinct situations (such as twosample test when the variances of both populations are believed to be the same).
 A twosample ttest in R for the example presented in class:
 An R example
Chapter 9  the chisquare test and twoway tables
 An R example
 A PDF with a chisquared test.
 Another site illustrating using R for chisquared test for twoway tables. The example uses a file with heart attack data which can be found here (please note that you will find there a number of other useful R examples). The particular file that needs to be read is Here is a local mirror of this site.
 An example of how to run the scripts and read data with R.
Chapter 12  oneway ANOVA
 R examples
 A nice example of oneway ANOVA with boxplots and linear model fitting. Also, illustrates working with lists ('sapply') and splitting data by levels of a factor ('split').
 An R example of oneway ANOVA with pairwise ttest (no data appears to be available, just the sequence of R commands).
 A very cojent explanation of 2way ANOVA.
More R resources
 A list of R tutorials.
 A list of R cheatsheets, especially this one.
 http://www.statmethods.net/  a reference for many commonly used methods.
 http://www.ogalab.net/RGM2/images.php?show=all&pageID=2007  a rich review of R graphical capabilities.
The final
 The Final Information  partially updated for Fall 2011