PinnedKaren Grace-MartinHow to Analyze Pre-Post DataOne area in statistics where I see conflicting advice is how to analyze pre-post data. I’ve seen this myself in consulting. A few years…Jan 22, 2013Jan 22, 2013
PinnedKaren Grace-MartinChoosing and Using Effect Size StatisticsIf you’re in a field that uses Analysis of Variance, you have surely heard that p-values don’t indicate the size of an effect. You also…Jan 13, 2011Jan 13, 2011
PinnedKaren Grace-MartinWhen it Makes Sense to Categorize a Continuous Predictor in a Regression ModelThree Situations When it WorksJul 24, 2009Jul 24, 2009
Karen Grace-MartinWhat is multicollinearity, really?What’s the difference between Mixed and Multilevel Models? What about Hierarchical Models or Random Effects models?Aug 211Aug 211
Karen Grace-MartinFour Weeds of Data Analysis That are Easy to Get Lost InEvery time you analyze data, you start with a research question and end with communicating an answer. But in between those start and end…Aug 16Aug 16
Karen Grace-MartinThree Designs that Look Like Repeated Measures, But Aren’tRepeated measures is one of those terms in statistics that sounds like it could apply to many design situations. In fact, it describes only…Aug 8Aug 8
Karen Grace-MartinThe Unstructured Covariance Matrix: When it Does and Doesn’t WorkIf you’ve ever done any sort of repeated measures analysis or mixed models, you’ve probably heard of the unstructured covariance matrix…Aug 7Aug 7
Karen Grace-MartinWhen a Variable’s Level of Measurement Isn’t ObviousA central concept in statistics is a variable’s level of measurement. It’s so important to everything you do with data that it’s usually…Aug 1Aug 1
Karen Grace-MartinStrategies for Choosing and Planning a Statistical AnalysisThe first real data set I ever analyzed was from my senior honors thesis as an undergraduate psychology major. I had taken both intro stats…Jul 10Jul 10
Karen Grace-MartinOutliers: To Drop or Not to DropShould you drop outliers? Outliers are one of those statistical issues that everyone knows about, but most people aren’t sure how to deal…Jun 263Jun 263