Day 7: STA205 - Introduction to Statistical Methods

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• Today we continue with Packet 03: Sampling Distribution of the Proportion.pdf
  • I want to start by sharing some success on the "normal curve" plotting front: my buddy Dan and his son Danny have constructed the first prototype of the super-duper "NKU Normal Curve Plotter". I'll show it off today, but I'll pass it around for you to look at. Soon you should be able to obtain your own personal plotter, for a very modest sum (a few bucks). More details to follow....

  • We're talking about proportion, at the moment, and so thinking of categorical variables, frequencies (counting), and relative frequency (which is to say "the proportion with a certain characteristic").

  • I begin with a rather odd tale, but you'll see that it is related to the important concept of sampling, and its relationship to the normal curve.

    I confess that, on Fridays, I may stop by DEPs just up the road to see what they've got on special. They surplus a lot of good beer, and I always need to take something up to Canada with me on Spring break, to please my Canadian friends (otherwise I wouldn't be welcome -- that's how shallow they are...:).

    My chums and I all like India Pale Ales (IPAs), which is neither here nor there for some of you (who shouldn't be drinking yet!). But I found three and a half cases of Christian Moerlein Bay Of Bengal Double IPA, and left DEPs happy....

    Oddly enough, the can doesn't have the alcohol content or IBU (International Bitterness Units) level on it (shame on Christian Moerlein!). So I was obligated to go out on the web for information, which I found on this site rating my Christian Moerlein Bay Of Bengal Double IPA. And that's where the sampling comes in.... literally!

  • So normal curves are going to come back up. On that note, I want to do a little experiment in a few minutes using some coin data. So I want each of you to flip a coin 20 times, and count how many heads you see. Record this for later.

• Links:
  • Please watch Brooke's Sampling distribution of the sample proportion at some point. It will help you finish off Packet 3.

  • The Standard Normal Table of probabilities.

  • Statcrunch instructions for packet 2 (and IMath homework):
    • Load the Stop and Frisk Data for packet 2. Load it by "WWW address", and make sure to set the delimiter to "comma" (because this is a "csv" (comma-separated values) file.
    • Once the data is loaded, click on "Graph" or "Table".
    • Alternatively, you may want to join my "group" on Statcrunch. That way you can access the data more quickly. It's Sta205-Long, if you want to add yourself into that group.
    • For the IMath homework, you'll need the Bipolar Depression Study data. Same thing: Load it by "WWW address", and make sure to set the delimiter to "comma" (because this is a "csv" (comma-separated values) file (or get it from the group).