Day 28: STA205 - Introduction to Statistical Methods

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• Announcements:
  • Your quiz is returned. No quiz this Friday!
  • Your Packet 12 IMath homework is due tomorrow.
  • Your Packet 13 IMath homework is due Friday, Cinco de Mayo (5th of May). It's optional, but will replace a weaker IMath score if you do it. You should do it anyway, to prepare for the final!

  • I marched in for Science in Washington, D.C. this weekend. Scientists make the funniest signs! Here's one for statistics class

    I marched for science because it breaks my heart to see our government defunding science, defunding the EPA (which protects our air, water, keeps us from mercury and lead poisoning, etc.), denying climate change, and then building up the military -- as though military weapons aren't built on science.

    I was looking at images of the march today, and came across a response after an article that bugged me: someone claimed that the people at the march weren't really scientists.

    I'm a scientist, and I was there. So was the former chair of NKU's math/stat department. Scientists were there.

• Today:
  • Today we wrap up Packet 12: ANOVA (we could say "multi-sample" inference (instead of just "two").

    "ANOVA" stands for "Analysis of Variance". Variance is another measure of spread or "variability": the square of the standard deviation. We will tend to use the ranges in the graphics to represent spread, and to give us some idea of the "F statistics" calculated.

    In this course we consider it more important to gain an intuitive idea behind the F statistic, rather than a computational one.

    By the way, the two sample unpaired design we just studied in Packet 11 is equivalent to ANOVA with just two samples.

  • Then it's on to Packet 13: Regression

    What so important about regression? We use it all the time. For example, to model CO₂ in the atmosphere:

    Here's a model of the Keeling data (xlispstat)

• Links:
  • The Standard Normal Table of probabilities.