| ## HomeMath 2200, Spring 2010
## Monday, May 10 Scaled final scores are (almost all) posted. ## Sunday, May 9The final exam is posted here. ## Saturday, May 8 1. The update for Question 25 on Exam 3 (throwing out Q25 for those who answered false) was reverted by Telesis. I'll fix it before making final grades. ## Wednesday, May 5The answers for the Fall 2009 Final Exam are: IIFFEBGCCBDBBEHIIEGHGAGCE. ## Tuesday, May 4 Let me take this time to remind you to fill out course evaluations. I understand that tomorrow 5/5 is the last day for evaluations. ## Monday, May 3The review session will be held tomorrow, Tuesday May 4th, in Seigle 103, from 8 - 10pm. ## Sunday, May 2 I'll be around my office at least between 12 and 3 Monday through Thursday this week. ## Saturday, May 1 1. My computer was a victim of the lightning on Friday. As a result, I'll be somewhat more difficult to reach by email. Please make sure to use the "@math.wustl.edu" address. ## Friday, April 30 Happy WILD! ## Wednesday, April 28The R transcript from this morning's class is posted. ## Wednesday, April 28 The R transcript from Monday's afternoon class is posted. (The morning class had a similar transcript.) ## Monday, April 26My usual office hours are Tuesday 12-2. To help you prepare for the final exam, I'll be around my office 2-4 as well. ## Sunday, April 25 The homework sets in the schedule are now complete. ## Friday, April 23I've posted the transcript of R commands from this morning's class. (The afternoon class had a similar transcript.) See Thursday's note below for how to get the cereals data into R. ## Thursday, April 22 I've posted the transcript of R commands from yesterday's afternoon class. (The morning class had a similar transcript.) ## Tuesday, April 20 Solutions for Exam 3 are posted here. They are brief, but I hope they are helpful. ## Monday, April 19 You should interpret your grade on Exam 3 as follows: 86-100 = A, 71-85 = B, 51-70 = C, 30-50 = D, etc. ## Friday, April 16Professor Sawyer has a nice page on doing statistics with a TI-83. It may be a useful reference, combined with the discussion from class. It includes the method for calculating invT on a TI-83. ## Thursday, April 15 Exam 3 is now posted. ## Monday, April 12 The review session is TONIGHT, 8-10pm, in ## Sunday, April 11 I've written an overview of topics for Exam 3. ## Friday, April 9 Related to the astrological data on CEOs from Wednesday: on this page is an analysis of the distribution of birthdays over the 12 months of the year. The author provides birthday data of 480,040 individuals, and finds more variation than can be accounted for by chance. ## Wednesday, April 7 The exam will cover from Chapter 17 through the first part of Chapter 26 (the chi-squared test for goodness of fit). ## Wednesday, March 31The applet for comparing Student's t-distribution with the normal distribution for various degrees of freedom is linked here. ## Monday, March 29 Class was cancelled Friday 3/26, due to a medical emergency. ## Sunday, March 21 I have rescored the exam, giving partial credit on the following problems: ## Wednesday, March 17A pdf of the exam is posted here. The correct answers are on mathlookup, as usual. ## Sunday, March 13 Akshay's scheduled office hours are cancelled, due to lack of attendance. You can still email him to set up a meeting. ## Sunday, March 13 Once more, our upcoming exam will cover ## Monday, March 8 The links section (at left), still has the link to the math department old exams page. I especially recommend the Fall 2009 and Fall 2007 exams from Math 2200. The relevant material is mostly from Exam 2, with a little bit (residuals and regression lines) from Exam 1. You should have a pretty good idea after the first exam of how our exams this semester will compare to these past exams. ## Monday, February 22The WebMD news article shown in class is linked here. Also available are another summary and the scholarly article itself (these may be available only from a Wash U ip address). ## Tuesday, February 16If anyone picked up an extra copy of the Student Solutions Manual (with a ripped top) at the review session, please email Shira Sacks (sesacks at wustl). ## Saturday, February 13The R commands that we demonstrated yesterday in class were as follows:
Reexpressing data works similarly with other R command, e.g. abline( lm(1/City.MPG ~ Weight)) cor(1/City.MPG, Weight) plot(sqrt(InsectSprays$count) ~ InsectSprays$spray) etc. ## Friday, February 12 pt 2The exam is posted here. The correct answers can be found on mathlookup -- note that both A and B received full credit on #6, and both C and I received full credit on #19. ## Friday, February 12 pt 1 You can look up your score and find out what you got wrong at the math scores lookup site. ## Thursday, February 11 To exclude outliers from analysis in R in the SAT Verbal vs SAT Math model, I first identified them as rows 66 and 162. I then gave the command: ## Monday, February 8 pt 2 The homeworks for Chapters 8 and 9 are posted in MyStatLab and the homework. Hint for Chap 9 #19 -- look for leverage points. | |||||||||||||

sat<-read.delim("Ch08_SAT_scores") | # read SAT scores data. See the note from Feb 3. | |||||||||||||

attach(sat) | # makes it possible to refer to variables in the sat table by their name alone, e.g. Verbal.SAT instead of sat$Verbal.SAT | |||||||||||||

plot(Verbal.SAT, Math.SAT, type='n') | # Set up the axis with the right scales for plotting | |||||||||||||

points(Verbal.SAT[Sex=='F'], Math.SAT[Sex=='F'], col='red') | # display points only of cases with Sex value of 'F' in color red | |||||||||||||

points(Verbal.SAT[Sex=='M'], Math.SAT[Sex=='M'], col='blue') | # do the same for males in color blue | |||||||||||||

l_Male=lm(Verbal.SAT[Sex=='M'] ~ Math.SAT[Sex=='M']) | # create linear models for males and females | |||||||||||||

l_Female=lm(Verbal.SAT[Sex=='F'] ~ Math.SAT[Sex=='F']) | ||||||||||||||

abline(l_Male, col='blue') | # draw the line of best fit for males and females in blue and red | |||||||||||||

abline(l_Female, col='red') | ||||||||||||||

Other commands of interest: 'l_Male' will display the linear model, including the line of best fit and r-value. 'sat[1,]' will display the first row of the data table. You might also draw the line of best fit for the entire data set, or try it for the gender-selected subpopulations with the previously-identified outliers removed. 'subset(sat, Sex=='F')' will construct a new data table consisting of the lines from sat with variable Sex having value 'F'. |

1. No Kendall or Spearman on the exam. Otherwise everything from Chapter 7 (and 2-6).

2. Answers from Fall 2009 Exam 1: FDGHBAFHBDACAIHHHEBGFGEBH. (No solutions will be provided.)

R code from today and homework later tonight...

An overview of topics (and some other information) for the first exam is available.

Of special interest from this document: Akshay's review session will be held Monday evening, 8 - 10 pm in 306 Seigle Hall.

On the day of the exam, you'll look up your room and seat at the math department seat lookup site. This has been added to the links.

The R calculations shown in class today were as follows:

1. The data file is Ch08_SAT_scores.txt. There are two lines at the end with periods in both column, which give R problems reading the file. Open the file with a text editor and remove these two lines. | |

2. sat<-read.delim("Ch08_SAT_scores") | # read SAT scores data |

3. sat | # display data |

4. plot(sat$Verbal.SAT, sat$Math.SAT) | # make scatterplot of quant vs quant data |

5. abline(lm (sat$Verbal.SAT ~ sat$Math.SAT)) | # display line of best fit |

6. cor(sat$Verbal.SAT, sat$Math.SAT) | # calculate correlation coefficient |

Preparing for exams: under the links section (at left), there is a link to the math department old exams page. I especially recommend the Fall 2009 and Fall 2007 exams from Math 2200. If you want to see an exam that I personally have written, then I would suggest looking at Exam 3 from Math 131 in Spring 2009.

An extra office hour: I'll be in my office tonight from 7:00 - 8:00 pm, but I have to leave fairly promptly at 8.

1) I've set my office hours to be Tuesday 12:00 - 2:00 pm. I'm still also pleased to make appointments for other times.

2) The instructions for using R are linked at left.

1) As announced in class, Akshay Honnatti is available to give comments on homework, and will have help sessions on monday and wednesday. I've updated the syllabus with his information.

2) The cost-of-living data, with OpenOffice code to separate it into 'bins' or 'buckets' to make a histogram is available. Its in OpenDocument spreadsheet format, which I understand is readable by recent versions of Excel (or with a filter to convert).

3) The Freakonomics blog story with an example of a pie chart used to present categorical data (talked about in 3:00 section) is linked here, and here is another nice presentation of categorical data.

4) The full set of Titanic data can be found here, if you're interested. The ASCII comma separated file is easily imported into OpenOffice or Excel.

Homework for Friday's up now. More schedule materials and syllabus updates will be up over the weekend.

Welcome to Math 2200! The Syllabus and Schedule are linked at the left, as well as MyStatLab, which we will be using for optional online homeworks.

To register for MyStatLab, follow these instructions. There should currently be two homeworks on the MyStatLab page: an orientation, and one for Chapter 2.

*Last modified May 14, 2010 *