This video shows how to obtain and install R on the Mac OS X platform. It also shows a few basic functions in R, such as how to install packages in R and load them for use. A PC version is here: How to Install R for Windows
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I have a saying that I like to tell consulting clients, which is easier said than done, but I think are words for doctoral candidates to live by: "The only bad dissertation draft is one that isn't turned-in." The most common factor that unnecessarily slows progress on a dissertation proposal or defense is a propensity to strive for the perfect draft. As a graduate student, we all fantasized of turning-in our first draft and having our advisor, being so amazed at its brilliance, insist that you accept your PhD on the spot...
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I received a great question this week, which asked: In order for a moderating relationship to exist, do the predictor IV and dependent variable need to be significantly correlated?". This is a question that I am asked a lot, partly because of the common confusion between mediators and moderators and the commonly held belief that an IV and DV should be related for mediation to be present (see my video blog on Mediators, Moderators, and Suppressors for more info on this topic). However, moderators are a completely different story...
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Preparing a dataset for analysis is an arduous process. Besides recoding and cleaning variables, a diligent data analyst also must assign variable labels and value labels, unless they choose to wait until after your output is exported to Microsoft Word. Unfortunately, that option only leaves additional opportunity for error and confusion, not to mention the inefficiency of editing tables in Microsoft Word...
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The video tutorial demonstrates how to make SPSS produce output tables in APA, doing much of the "heavy lifting" for you!
Read MoreWhen I hear the word "residual", the pulp left over after I drink my orange juice pops into my brain, or perhaps the film left on the car after a heavy rain. However, when my regression model spits out an estimate of my model's residual, I'm fairly confident it isn't referring to OJ or automobile gunk...right? Not so fast, that imagery is more similar to it's statistical meaning than you might initially think.
Read MoreMulticollinearity said in "plain English" is redundancy. Unfortunately, it isn't quite that simple, but it's a good place to start. Put simply, multicollinearity is when two or more predictors in a regression are highly related to one another, such that they do not provide unique and/or independent information to the regression.
Read MoreWhile there is no "magic bullet" to make stats and data analysis easy to understand and helpful in our research, there are some things that you can do to avoid pitfalls and help things run smoothly. This "top ten" list offers a few of those things that I think you will find helpful! I'll be posting a video of this list later today on my Stats Videos page.
Read MoreThe Bonferroni correction is only one way to guard against the bias of repeated testing effects, but it is probably the most common method and it is definitely the most fun to say. I've come to consider it as critical to the accuracy of my analyses as selecting the correct type of analysis or entering the data accurately. Unfortunately adjustments for repeated testing of hypotheses, as a whole, remains something that is often overlooked by researchers and the consequences may very well be inaccurate results and misleading inferences. In this independence day blog, I'll discuss why the Bonferroni Correction should be as important as apple pie on the 4th of July.
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This video podcast demonstrates how to use the rarely-used "Define Variable Sets" function of SPSS (PASW) to organize and keep focused on your data.
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The video tutorial demonstrates how to make SPSS produce output tables in APA, doing much of the "heavy lifting" for you!
Read MoreAnyone that has taken a statistics class has probably learned about transforming data, at one time or another (although you may be in denial about it).In short, you may want to transform your data if you need to perform a parametric analysis, but the inherent assumptions are violated in your dataset.
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Mediators, Moderators, and Suppressors are two of the most often confused statistical concepts in social science research. Our first installment of The Stats Make Me Cry Guy's Deviant Square Video Podcast clarifies the confusion that surrounds these concepts, and hopeful gets a laugh or two in the process!
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