Pronunciation Guides for Mathematical Notation, Expressions, and Greek Letters

When doing research in psychology you are sometimes required to study new statistical or mathematical techniques on your own. However, mathematical books rarely tell you how to pronounce the mathematical symbols. And even if you know how to pronounce the symbols in isolation, this does not guaranty that you can pronounce a mathematical expression made up of multiple symbols. Being able to read mathematical notation is a basic first step in aiding memory and conceptual understanding. The following links provide resources on reading mathematical symbols and provide a good reference if you encounter symbols and expressions with which you are not familiar.

Mathematics Pronunciation Guides

• VÄliaho's guide to Pronunciation of Mathematical Expressions: This is the place to start. It covers many important rules in a 3 page document
• Handbook for Spoken Mathematics: If VÄliaho's guide did not meet your requirements, check out this extensive resource. It covers many major branches of mathematics such as logic and set theory, geometry, statistics, calculus, and linear algebra. It is the most comprehensive guide that I have found with around 100 pages and around 500 symbols with pronunciation. I'd recommend studying all the symbols if mathematical pronunciation is an issue for you. The symbols are distributed over many pages making it a little difficult to look up a single symbol of interest. Also, when a choice exists, the guide often chooses a more verbose and less ambiguous form of pronunciation. For example, it suggests for "x_i", "x sub i" instead of "x i". This emphasis on unambiguous verbal communication is sometimes more than required when verbalising the symbols in your head or when verbalising symbols in a context where the actual symbolic math is also displayed.
• RPI's Saying Mathematics Guide
• Oanca et al's Reading Mathematical Expressions
• Wikipedia guide to mathematical symbols: meaning of common mathematical symbols with links to their meaning.
• Greek letters: Lower and upper case Greek letters with pronunciation
• Tips on displaying formulas can even be useful for some obscure mathematical symbols

The other option is to actually listen to mathematics lecturers and assume that the pronunciation will rub off: see my earlier post on free online mathematics video courses.

Books on mathematical pronunciation

• Lawrence Change (1983). Handbook for Spoken Mathematics: (Larry's Speakeasy).

Related Posts

• Tips on reading mathematics
• Sites that list free online mathematics books
• Videos on R

Introduction to Statistical Modelling in Psychology: NSS Presentation

Today I gave an introductory talk for the Neuropsychological Students’ Society at the University of Melbourne on the topic of Statistical Modelling in Psychology.

The slides with notes from the talk are available for download at the following link: Introduction to Statistical Modelling in Psychology.

Bootstrapping and the boot package in R

I was recently asked about options for bootstrapping. The following post sets out some applications of bootstrapping and strategies for implementing it in R. I've found bootstrapping useful in several settings:

• where the statistic I'm interested in is a little unusual: the average R-square across five separate regressions; the difference in the average correlation of a set of variables between two groups
• non parametric statistics, such as the median
• when assumptions such as normality of homoscedasticity are not satisfied

Self-Archiving of journal articles in academia

I'm a big fan of academics who post copies of their journal articles on their own website (e.g., here and here and here). Even if my university has online subscriptions to most journals, it is just more convenient to access all of a person's work in one place. Such articles are also typically then available through Google Scholar. It also opens the work up to others outside of academia who do not have access to university journal subscriptions. Given that academic work is typically directly or indirectly funded by public money, this seems particularly important.

I have found Sherpa Romeo to be a useful site for looking up the standard publisher copyright transfer agreement for different journals. This can be useful in selecting a journal outlet that allows for publishing on your own website. It also sets out the conditions for putting journal articles on your own website.

See here for a discussion of author rights.

Endnote Collaboration

I'm currently exploring options for using Endnote for collaboration:

UQ has a nice discussion of strategies for collaborating with Endnote.

I'm also considering using the Endnote web option.

Statistics for a Psychology Thesis

In 2007 I presented a talk to postgraduate psychology students at The University of Melbourne. As part of the talk I produced a handout which summarised many of the key points that I felt were relevant for such an audience who needed to complete a thesis involving quantitative analysis. Reading over it two years later, I still agree with the ideas, even if my understanding may be a little more nuanced. For example, I'd now see meta-analytic thinking as a simple version of Bayesian statistics. Anyway, I thought I'd post it on the blog.
The audio (17MB) for the talk is available online, as are the Slides, and a PDF version of the content below.

Online Mathematics Video Courses For Self Study in Psychology

This post provides links to free online video courses on mathematics and statistics.

Verifying How Composite Scores Have Been Computed

This post sets out a procedure for checking how a composite was computed from items. This is particularly useful when working with self-report psychological scales and composite ability tests. Computing total scores for a series of subscales and total scores on personality tests and other self-report inventories can be fiddly business, and errors often arise.

Calculating Composite Scores of Ability and Other Tests in SPSS

Researchers in psychology often have a large number of variables. Science aims for parsimonious explanations of the world. Thus, the challenge is to develop a principled approach to dealing with the multiplicities that arise in psychological research. One common approach is to combine tests that measure similar things into composites. This post looks at how to form composites. The emphasis is on settings where you have multiple ability tests and you want to create a composite ability factor. Also, particular emphasis is given to how to do it in SPSS.

Inquisit: Simple Reaction Time, Four Choice Reaction Time, and Typing Test

In 2007 I was looking for a tool for running psychological experiments online. It was important that the online tool could record reaction time. After a little exploration I started using Inquisit.

I’ve attached a script that I wrote which provides a basic measure of simple reaction time, four-choice reaction time, and a typing test. I thought I’d make the script available for others to use and modify. The program was written for Inquisit 3.0. The Inquisit website has a pile of additional scripts. It also has a fully functional trial-version of the software.

Click on the link below to download the script. Change the file extension to ".exp" to associate with Inquisit.

Simple RT, 4Choice RT, Typing Test: Inquisit Script

Photos from My Office - The University of Melbourne

For all its quirks, the Redmond Barry Building provides some very nice views.

User Interface for R: StatET and Eclipse

R is tremendously flexible. It’s flexible in how commands can be written, and it’s flexible in the user interface that can be used to run it. I’ve been playing around with different user interfaces on Windows for a while now.

Saving Citation Information from Google Scholar

I have often wanted to be able to export citations from Google Scholar into Endnote. While Google Scholar makes it easy to do this for single articles, it does not at present permit you to export an entire search.

I’ve found a work around. Anne-Wil Harzing’s Publish or Perish Software (free) searches Google Scholar and allows you to export a file that contains the ciation information of the entire search. This can then be imported into Endnote. It also exports in Bibtex and CSV format. 

It’s also a great way to assess the impact and citation rates of individual scholars, journals, and particular articles.

Books on Writing, Grammar, and Style in Psychology and Beyond

This post lists some books on academic writing, which I've found useful.

Assorted issues with Multiple Regression and Moderation

1. Do variables in moderation have to be normally distributed before centering? 

No, normality is not a requirement. However, you could apply a transformation if you felt it was justified, such as when it better reflects the meaning of the variable.

See the following for a discussion of issues in transformations: 

http://pareonline.net/getvn.asp?v=8&n=6

Assumptions in moderation are the same as in normal multiple regression. They mainly concern the pattern of the residuals. For a discussion see: http://www.statisticshell.com/multireg.pdf

2. Do I use the R squared or adjusted R squared when reporting a multiple regression?

You can use either or both. The larger your sample, the smaller the difference is between adjusted R square and R-squared. R-squared is a biased estimate.

3. p=0.52, is that still significant?

Jacob Cohen once said something along the lines that surely God must love .06 almost as much as .04. 

You can write p = .05

Whether this is statistically significant depends on your alpha. If your alpha is .05, then your obtained p value is not less than .05, and thus, it is not statistically significant. Reflecting the seemingly arbitrary cut-off consequences off null hypothesis significance testing, researchers often write that there was a trend toward significance when p <.10 and >=.05.

4. Would a significance level of 0.06 be slightly significant or not at all?

Trend toward significance is a common label, see above.

5. Do you have any examples of how to write up a moderator regression? 

Frazier, P., Tix, A., & Barron, K. (2004). Testing moderator and mediator effects in counseling psychology research. Journal of Counseling Psychology, 51, 115-134.

McAlister, A. R., Pachana, N., & Jackson, C. J. (2005). Predictors of young dating adults' inclination to engage in extradyadic sexual activities: A multi-perspective study. BRITISH JOURNAL OF PSYCHOLOGY, 96(3), 331.

This article is online at:

http://64.78.45.9/publications/411.pdf

Single Group Correlational Study: Basic Analyses

This post sets a basic procedure for analysing a single group observational study in psychology. It aims to provide a starting point, particularly for researchers who do analyse data infrequently.

Formatting Correlation Matrices in Psychology

Researchers in psychology often want to present a correlation matrix of the main variables in a study. This post sets out one way of producing a formatted correlation matrix that conforms to APA style.

Avoiding typing references into Endnote using Google Scholar

This post provides a tip for using Google Scholar to make importing references more efficient.

Saving Tab Delimited Text Files in Excel without Warnings

Since using R, I have started generally storing my data in tab delimited text files. I tend to edit this data in Excel. Excel is easier to use than the current editor built into R.

Basic Analyses of a Dyadic Data Set

This post follows on data manipulation for dyadic data. Once the pragmatic issue of merging data files was resolved, the researcher was interested in considering statistical analysis options for data involving measures of the same variables on a female and her partner.

Merging Data Files for Dyadic Data Analysis

The following post discusses data management for dyadic data.

Longitudinal Data with Varying Numbers of Time Points using SPSS

Context:
I recently chatted with a researcher who had data in the following format: around 20 participants; participants completed between 5 and 15 sessions, but some sessions involved missing data and sessions could be classified into one of five phases. For each session there were a few measurements. There were also a number of baseline measures. The challenge was how to make the most of the data file. The following were a few recommendations I made.

Carryover Effects in Repeated Measures Designs

This post discusses the issue of carryover effects in repeated measures designs. Ways of assessing and dealing with carryover effects are discussed. I then apply the concepts to an example from my own research looking at personality faking.

Causality and Mediation Analysis

This post discusses issues with causal inference in mediation analysis. It proposes a set of steps that researchers can use when analysing and reporting mediation analyses.

Using R to test for significant differences between two nonindependent correlations

I was recently asked about a quick and easy way to see whether the correlation between IV1 and DV is statistically significantly different from IV2 and DV. The follow post set out how this analysis can be conducted in R. The instructions assume that you have never used R before and are running Windows.

Getting Started with Mediation and Moderation: SPSS and R Resources

The following post sets out resources for getting started with mediation and moderation analysis.

First Post

Okay. So this is the first post.
I'm hoping that this blog will be useful to others.
In particular I do a fair amount of statistical consulting to psychology and other social science researchers.
I figured this could be a place to maintain answers to common and not so common questions.

I'm also a big fan of R (www.r-project.org/). I'm keen to share some of the little tricks that I've learnt over the while in how to learn and get the most out of R.

I also plan to brainstorm various ideas in relation to my various research interests, which currently tend to be associated with industrial / organisational psychology and social network analysis.

Anyway, we'll see how it evolves over time.