GRADED EXERCISE ON MEDIATION AND SEQUENTIAL REGRESSION (CLOSED)
How to do the graded exercise in R (text)
Answers to the graded exercise (text)
This exercise MUST be submitted by 1:00 PM Tuesday, May 3rd. No late exercises this time. Grades are due!

IMPORTANT NOTE: If you are not seeing active links below where I say there should be active links, it is probably because your browser is pulling an old version of the page out of its cache. Press Ctrl-R (Command-R on a Mac) to reload the page. That should activate the links.

Data File Retrieval

Articles

• Statistical Benchmark Comes Under Fire (Sun News, 2019)
  topics: statistical significance
• What Is Normal Human Body Temperature?
  topics: single- and two-sample t-tests; data: normtemp.txt
• Superiority of Women (in Statistics)
  topics: t-test and chi-square; data: Brooks.txt
• Wolves Outperform Dogs
  topics: t-test, single-factor ANOVA, etc.; data: wolves.txt
• Algebra Grades and Learning Environment
  topics: single-factor ANOVA; data: Ashby.txt
• Incidental Learning
  topics: factorial ANOVA; data: eysenck.txt (and others)
• Narcissism on Facebook
  topics: unbalanced factorial ANOVA; data: narcissism.txt
• Sign Learning in Chimps
  topics: repeated measures ANOVA; data: chimps.txt, chimpslong.txt
• Chocolate Consumption and Nobel Prizes
  topics: simple correlation and regression; data: chocolate.txt, chocolate_new.txt
• Getting What You Pay For (in Education)
  George Will's Editorial Mentioned in Article
  topics: multiple regression (and confounds); data: Guber.txt, guber.csv
• Hippocampal Volume and Schizophrenia
  topics: analysis of covariance; data: hippocampus2.txt (also hippocampus1.txt)
• Sensation Seeking and Alcohol Use in College Students (This is a tough one! Be patient with it.)
  topics: hierarchical regression, mediation
• Social Networking and Social Outcomes
  topics: hierarchical regression

IMPORTANT NOTE: Some of the videos that are posted here were recorded during Fall 2020 and I wasn't smart enough at the time not to mention dates or times in those videos. Please IGNORE any reference to days or times in these videos!

• ===== WEEK 1: January 10th =====================(123)
• Read the syllabus!
• Do this exercise: Introduction to the Basics of Statistics (html)
  (Very similar but not identical to the PDF version under review materials.)
• Do this exercise: Review--Required Calculations (html - interactive)
• Complete and submit this short exercise. You must submit this exercise so that I know you are "attending" the class. I will soon have to report this to the registrar, and if you are "not attending," the registar's office will drop you from the course roll.
  Week One Exercise -- Must be submitted by Friday at noon! (removed)
  
  
• ===== WEEK 2: January 17th =====================(116)
• Assignment: Review these slides: How To Speak Statistics (PDF - slides only)
  Same slides embedded in an html page: How To Speak Statistics (html - slides only)
• Or watch this video (same slides): How to Speak Statistics (mp4 - 50 min.) (removed)
  FYI: It is not Thursday, August 27th. Ignore that.
• Read this article: Statistical Benchmark Comes Under Fire (Sun News, 2019)
• ====================Using R Videos====================
• Watch this video: How To Install R on Your Computer (mp4 - 11.5 min.)(removed)
  It is not absolutely necessary to have R on your computer, but it would be very convenient! The following video illustrates a work-around if you don't want to or can't install it on your own computer. For example, you cannot put R on a Chromebook, but you can use RStudio Cloud instead.
• Watch this video: Introduction to R and RStudioCloud (part 1) (mp4 - 61 min.)
  Don't just watch! Get R open and follow along. You will need these skills VERY SOON.
  And work with the practice data at the end of this video.
  I will answer questions now. I will not during next week's graded exercise. YOU'VE BEEN WARNED!
• Watch this video: Introduction to R (part2) (mp4 - 59 min.)
• Handout to accompany these videos: Introduction to Using R
• If you need it: How to retrieve data from the website (mp4 - 10 min.)
  Note: newer versions of R will handle the https protocol. (No need to erase the s.)
• Optional: How to enter your own data into R (mp4 - 38 min.)
  You may not be able to follow the ANOVA illustration in this video YET!
  Note: use read.table(header=T, stringsAsFactors=T, text=" in the script window if your R version is 4.0 or newer.
• Optional: One more way to enter your own data (mp4 - 9 min.)
  
  
• ===== WEEK 3: January 24th =====================(109)
• Some practice problems to hone your R skills (html)
• Read this article: Superiority of Women (in Statistics) (PDF)
  Same article embedded in html: Superiority of Women (html)
  Answer these questions as you read: Some questions to guide your reading (text)
  
• More Practice with R Using Data from Brooks (1987) (html - interactive)
  
• GRADED EXERCISE covering: Basics of Statistics, Required Calculations, How to Speak Statistics, Statistical Benchmark Comes Under Fire, Introduction to R (both parts), Using R to do t-tests and chi-square tests
  GRADED EXERCISE (removed)
  This exercise must be submitted no later than Saturday, Jan 29th, at noon.
  
  
• ===== WEEK 4: January 31st =====================(102)
• Watch this video: Simple ANOVA part 1 (mp4 - 35 min.)(removed)
• Ignore any references to RWeb in this video. Make sure you can duplicate the analysis on the caffeine data in R. You can get the data from the website in the form of a data frame using the following commands (which now work--data file is now properly formatted--and you can copy and paste them if you have trouble typing correctly):
  

  file = "http://ww2.coastal.edu/kingw/psyc480/data/caffeine.txt"
  CA = read.table(file = file, header=T, stringsAsFactors=T)

• Simple ANOVA (same slides without my lecture) (PDF - 22 slides)
  Simple ANOVA (same slides embedded in html page)
• Watch this video: Simple ANOVA part 2 (mp4 - 44 min.)(removed)
• Watch this video: How to do simple ANOVA in R (mp4 - 28 min.)(removed)
• Do these practice problems in R: ANOVA Practice Problems to Try in R (text)
• Answers to those problems in R: Answers to the Practice Problems (text)
• Do this exercise: More Post Hoc Tests (html - interactive)
  
  
• ===== WEEK 5: February 7th =====================(95)
• Do this exercise: Simple ANOVA Exercise (test yourself) (html - interactive)
• Read this article: Algebra Grades and Learning Environment
  Here are some tips to help you over the hard parts (text)
  After you've read the article and the tips, fetch the Ashby.txt dataset from the website and see if you can duplicate the analysis in the article. (See the tips link for details.)
• Do this exercise: ANOVA and Regression (html - interactive)
• Graded Exercise Two on Simple ANOVA (removed)
  This exercise must be submitted not one second later than noon, Saturday, February 12th.
  
  
• ===== WEEK 6: February 14th ====================(88)
• Watch this video: Video lecture on factorial ANOVA (mp4 - 38 min.)(removed)
  Just the slides, no lecture: Same slides without me coughing (slides - PDF)
  Just the slides, no lecture: Same slides embedded in an html page (html)
  Note: when fetching the oddmonkeys data, use the following commands:
  

  file = "http://ww2.coastal.edu/kingw/psyc480/data/oddmonkeys.txt"
  OM = read.table(file=file, header=T, stringsAsFactors=T)

• (OPTIONAL): Hand Calculations for Factorial ANOVA (text)
  (OPTIONAL): SPSS Tutorial on Factorial ANOVA (YouTube)
  (OPTIONAL): How To Do Factorial ANOVA in Vassarstats (html)
• Watch this video: The logic of factorial ANOVA (mp4 - 57 min.)(removed)
  Make sure you can duplicate the analysis in this video in R!
  Just the slides, no lecture: Same slides but no voice lecture (PDF embedded in html)
  
• Do this practice problem: A factorial ANOVA practice problem (text)
  This dataset can be loaded from the website in the usual way. Try to work through it before you resort to watching the video. The dataset is eysenck.txt.
  
• (OPTIONAL): If you want to read the original article describing the research from which these data were derived, scroll up to the Articles box and click the link on Incidental Learning.
  Watch this video: How to do this problem in R (mp4 - 59 min.) (removed)
• Look over this handout: Visualizing and describing interactions (PDF embedded in html)
  Lecture on the handout: Lecture on the interactions handout (mp4 - 50 min.)(removed)
  Make absolutely certain that you understand this. If you don't, ASK!
• Do this exercise: Factorial ANOVA from Beginning to End (html - interactive)
  
• Do these practice problems: Practice problems for factorial ANOVA (text)
  These practice problems also have NEW INFO about weighted vs. unweighted marginal means. Make sure you see that!! It's going to be very important very soon.
  Same problems with some answers: Practice problems for factorial ANOVA (with some answers) (text)
  
  
• ===== WEEK 7: February 21st ====================(81)
• Review! Review of Factorial ANOVA (html - interactive)
• What if it's not balanced? Slides and Video Lecture on Unbalanced Designs (mp4 - 45 min.)
  Same slides (almost!) but no lecture (html)
  This is difficult material. Don't put off looking at it. You will have questions!
• Do this exercise. Exercise on Unbalanced Factorial Designs (html - interactive)
• Watch this video. Type II and Type III SSes in R (mp4 - 39 min.) (removed)
  Make sure you can duplicate my analysis in R. The aovIII() function now works slightly differently than it did when I made this video, but it shouldn't be enough to throw you off.
• Do this execise. Unbalanced ANOVA Practice Exercise (html - interactive)
• Do these practice problems. Unbalanced Designs Practice Problems (html)
  Here are the answers. Answers to Practice Problems (text)
  
  
• ===== WEEK 8: February 28th ====================(74)
• GRADED EXERCISE on balanced factorial ANOVA is here. CLOSED! Can no longer be submitted.
  Graded exercise on balanced factorial ANOVA (removed)
• GRADED EXERCISE on unbalanced factorial ANOVA is here. CLOSED! Can no longer be submitted.
  Graded exercise on unbalanced factorial ANOVA (removed)
  
  
• ===== SPRING BREAK! March 7th ================(67)
  
  
• ===== WEEK 9: March 14th ======================(60)
• Repeated Measures ANOVA Slides and Video (mp4 - 55 min.)(removed)
  Same slides no me talking (pdf embedded in html)
• Exercises on repeated measures ANOVA (html)
• Treatment by Blocks (html - interactive)
  How to use the script window to enter these data (mp4 - 14 min.)
• Review of Repeated Measures Designs (html - interactive)
• Mixed Factorial Designs (html - interactive)
  
  
• ===== WEEK 10: March 21st =====================(53)
• Preparation for repeated measures and mixed factorial ANOVA Graded Exercise (html)
• Graded exercise on repeated measures and mixed factorial designs (removed)
  Due no later than noon on Thursday, March 24th.
• Introduction to Regression Analysis
  • Watch this video: Review of Simple Regression (mp4 - 30 min.)
  • Same slides without my gravelly voice: Review of Simple Regression Slides (PDF embedded in html)
  • practice problem: There is a dataset at the website called alcohol.txt that can be loaded into R in the usual manner. The data were taken from the Family Expenditure Survey of the British Department of Employment. Average expenditure in pounds (money!) per week by family for alcohol and tobacco products in 12 regions of Great Britain are the variables. See if you can find a relationship. There is an obvious outlier. Does the relationship change much if this outlier is dropped from the data?
  • Read Chocolate Consumption and Nobel Prizes
    This is a fun one. You'll like this one. (Or do I not understand the meaning of the word "fun"?:)
  • The data from Messerli's article are in chocolate.txt at the website. See if you can find the appropriate correlations and regression equation, etc.
  
  
• ===== WEEK 11: March 28th =====================(46)
• More on regression in R: Regression in R (mp4 - 53 min.)
  Try to ignore the throat clearing. Also ignore references to "the html page" and "the dataset" at the end of this video. I have no idea what this guy is talking about. Ignore any references to Rweb. We're not using this semester. Instead, do the following exercise, which uses Messerli's data.
• Do this exercise on regression (html - interactive)
• And finally, here is a little quiz to see if you're getting this regression stuff.
  Regression quiz (not submitted) (html - interactive)
• Solution to the new chocolate problem if needed. (mp4 - 13 min.)
• Two practice problems and some stuff about R (mp4 - 18 min.)
• Introduction to Multiple Regression
  • Read this short newspaper editorial. (png image)
    
  • Read this article from the Journal of Statistics Education. (PDF embedded in html)
  • Introduction to Multiple Regression (mp4 - 58 min.)
    (As usual, ignore references to days, dates, and times. in this lecture. Also, ignore any refs to Rweb. You'll soon understand why we're not using it!! Here is a link to the dataset: Guber.txt.)
  • Same slides but no voice lecture (PDF embedded in html)
    Crank up R and make VERY SURE you can repeat the analysis shown in these slides!!!
• Two Problems in Multiple Regression (text)
• Scottish Hill Racing, Etc. (html - interactive)
• Graded exercise on simple and multiple regression coming soon (but not this week).
  
  
• ===== WEEK 12: April 4th =======================(39)
• Introduction to Nonlinear Regression (html - interactive)
  DO NOT wait until the last minute to try to learn this. This is HARD!
• Everything Interesting is Nonlinear (html - interactive)
• Graded exercise on regression! (CLOSED)
  This exercise is due not one second later than noon on Saturday, April 9th.
  
  
• ===== WEEK 13: April 11th ======================(32)
• WATCH THIS VIDEO! Answers to graded exercise 6 (mp4 - 61 min.)(removed)
• Analysis of Covariance (mp4 - 59 min.)
  The handout upon which the above video is based (text)
• Go to the Articles box above and read Hippocampal Volume and Schizophrenia
• ANCOVA Exercises (html)
• A Few More Practice Problems You May Want To Look At (text)
  Answers to the Few More Problems (text)
• Graded exercise 7 on ANCOVA (CLOSED)
  ANSWERS (text)
  
  
• ===== WEEK 14: April 18th ======================(25)
• Introduction to mediation analysis and how to do it in R (mp4 - 68 min.)
  Notes on this video:
  1) There are no slides or other notes. You have to take your own notes.
  2) You do not have to delete anything from a data frame or rearrange the columns to do mediation analysis. I just did that to make things easier to understand.
  3) I am still checking to find out what the deal is with the standard errors in the mediate function results. Watch this space! (The standard errors are correct. I was reading the wrong line in the lm output! See the following video for details.)
• Mediation diagram from the video above (png)
• Mediators and Sequential Regression (mp4 - 39 min.)
  Same slides but no voice lecture (PDF embedded in html)
  Note: This video contains the answer to one of the problems in the following exercises.
• Mediation exercises (text)
• Hierarchical (Sequential) Regression (html - interactive)
• Some practice problems for sequential regression (text)
  
  
• ===== WEEK 15: April 25th ======================(18)
• Good Old Fashioned Hierarchical Regression (html)
• Lunacy (final example of hierarchical regression) (html - interactive)
• GRADED EXERCISE ON MEDIATION AND SEQUENTIAL REGRESSION (CLOSED)
  This exercise MUST be submitted by 1:00 PM Tuesday, May 3rd. No late exercises this time. Grades are due!

OPTIONAL READINGS

• Introduction to the Basics of Statistics (PDF)
• Research Design (some basic stuff) (PDF)
• If you don't know how to round off, here is an article you should read at least the first four sections of (through 4 Tie-breaking): Rounding (external). The majority of students who take this class don't know how to round off! But rounding errors are errors and will cost you points on exams. You can skim or skip lightly over the sections called "Rounding to a specified increment" and "Rounding to integer." Be sure to read "Tie breaking", however. In this class, we will follow the "Round half to even" rule. Be sure you read far enough to find out what that is!
• Here is a short course on rounding.
• Likewise, if you don't have an understanding of significant figures (significant digits), you should read this article: Significant Figures (external).
• If you are not familiar with scientific notation for large and small numbers, you should read about it here: Scientific Notation (external). In particular, pay attention to "E notation." You MUST know how to deal with this! I am not going to cover it in class! This is something you should have learned YEARS ago. Our software will often print very large and very small numbers in scientific notation. I will NOT accept scientific notation in answers on tests, however. You need to know how to convert!
  
  This class will be a test of your basic math and algebra skills. If you are "not a math person," you are definitely in the wrong place!!
  
  Here are some math errors I see commonly in this class. If you have any of these problems, NOW is the time to get them remedied. This is not a elementary math class. We do not have time to learn basic math in here!
  • Not understanding order of operations.
  • Not understanding the difference between positive and negative numbers.
  • Not understanding rules for signs (negative times negative is positive, etc.).
  • Not understanding greater than and less than.
  • Not understanding how decimal numbers between 0 and 1 work. (Absolutely crucial!!)
  • Not understanding fractions and proportions.
  • Not understanding that the square of a number can't be negative (believe it or not).
  • Not understanding square roots and logarithms.
  • Not understanding the rules for exponents.
  • Not understanding basic factoring of a simple algebraic expression.
  • Not understanding simple linear equations (slope, intercept, etc.).
  • Not understanding how to read a graph and extract information from it.
  • The list could go on (and on and on!), but I'd say those are the most important ones.

R Stuff For People Who Want It

• Link to the R Project home page (get R here) (External link)
• Download page for RStudio (optional) (External)
• RStudio Cloud (online interface to R)
• Rweb (online interface to R)
• R-Tutorials
• Three YouTube Videos About R (External)
  • What's Up With R
  • Reasons To Learn the R Programming Language
  • Obtaining and Installing R

Other Stuff For People Who Want It

• How To Do Statistics On The TI-89 Calculator
• tables
  • z-table
  • t-table (more alpha levels)
  • t-table (more dfs)
  • F-table
  • Bonferroni adjusted critical t values
  • r-table (critical values for Pearson r)
  • chi-square table
• Vassarstats (online statistics analysis)

Online Statistics Books (these are all external links)

• Online Statbook dot com
• Lowry's statbook at Vassarstats
• A New View of Statistics (Sportscience)
• Handbook of Biological Statistics