Descriptive Statistics

It's everybody's favorite time of year: the time in AP Psychology class where we closely examine how descriptive statistics (particularly, standard deviation and z-scores) help us make sense of test data.

To help with practice on basic descriptive statistics, students should complete this PsychSim Module on Descriptive Stats. Lost the worksheet you got in class? You can print another one here. Just note that it is two pages, so be sure to complete/print both sides.

Still lost when it comes to normal distributions, z-scores, and percentile ranks? You might wish to review this video from a fellow AP Psych teacher, who has posted it to help you with your review.

Math Invades Psychology Class




Frequency Histogram for Composite Scores on Final Exam

 Students tend to have strong feelings about mathematics...so when the topic comes up in AP Psych I usually get a "love it" or "hate it" reaction from students. Regardless of one's emotional response to math, however, it is helpful to know some basic statistical concepts if you're trying to make sense of some things in psychology, particularly test score interpretation (e.g. in intelligence and personality testing).

So, in addition to the practice on basic descriptive statistics students are completing for tomorrow (to access the accompanying PsychSim Module for this WS, click here), we've been using some meaningful examples of score distributions to become more comfortable with the topic. Particularly, we've been examining performance data from our 1st Semester final (which, as the frequency histogram above illustrates, distribute rather normally).

However, if you're still feeling confused about z-scores, the normal curve, percentile ranks, and standard deviation, there are a number of great websites out there to give you some guidance (unfortunately, our text does not go into a great amount of detail about these statistical concepts). Consider consulting any of these for review:

• A Beginner's Guide to Descriptive Statistics (includes examples and procedure for calculating standard deviation).
• Online calculator for descriptive stats (can copy & paste data and it will give you the standard deviation, among other measures)
• Handy, printable guide to the Normal Curve & Z-scores
• Statistics Tutorial: Standard Normal Distribution (& z-scores)

If you come across any other sites that you feel would be helpful to a beginning psych student, please include them in the comments section. I'd love to add them to my list.