Counting pillars and posts

The students were paired off on day one and told to count the number of pillars and posts on campus. The only definition was that the pillar or post should be standing free from a structure – a not a wall element.

Counting pillars
Counting pillars

I did not mention how to count the two-story tall pillars for the A and B buildings. This led to a natural introduction of the importance of definitions. The counting took 25 minutes, some finishing faster, singular groups slower.

M8 M9 M10
275 258 266
228 261 281
152 281 283
312 286 285
316 298 285
305 293
309 296
310 326
sample size n 5 8 8
275 unspecified how A, B bldg pillars counted
258 A, B, pillars counted as one top to bottom
305 A, B pillars counted as two top to bottom

A good sample description must include clear definitions. In the 9:00 class the students noted that they were counting the pillars differently for the A and B building. Some counted the pillar top to bottom as one pillar, some counted “per floor” and wound up with double the number of pillars. I suspect this happened at 8:00 as well.

Nancyleen tallies data

Note that the 152 is an outlier: that group did not go all the way to the cafeteria – they each thought the other one had gone there. This provided a chance to note that z-scores can be used to help identify outliers that could potentially be data errors.


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