Monday, October 17, 2016

Pew Research's "The art and science of the scatterplot"

Sometimes, we need to convince our students that taking a statistics class changes the way they think for the better.

This example demonstrates that one seemingly simple skill, interpreting a scatter plot, is tougher than it seems. Pew Research conducted a survey on scientific thinking in America (here is a link to that survey) and they found that only 63% of American adults can correctly interpret the linear relationship illustrated in the scatter plot below. And that 63% came out a survey with multiple choice responses!

How to use in class:
-Show your students that a major data collection/survey firm decided that interpreting statistics was an appropriate question on their ten-item quiz of scientific literacy.
-Show your students that many randomly selected Americans can't interpret a scatter plot correctly.

And for us instructors:
-Maybe a seemingly simple task like the one in this survey isn't as intuitive as we think it is!

Monday, October 10, 2016

Pew Research's "Growing Ideological Consistency"

This interactive tool from Pew research illustrates left and right skew as well as median and longitudinal data. The x-axis indicates how politically consistent (as determined by a survey of political issues) self-identified republicans and democrats are across time. Press the button and you can animate data, or cut up the data so you only see one party or only the most politically active Americans.
The data for both political part goes from being normally distributed in 1994 to skewed by 2014. And you can watch what happens to the median as the political winds change (and perhaps remind your students as to why mean would be the less desirable measure of central tendency for this example). I think it is interesting to see the relative unity in political thought (as demonstrated by more Republicans and Democrats indicating mixed political opinions) in the wake of 9/11 but more politically consistent (divided?) in the more recent past.

Depending on how deep you feel like going with this example, it can also illustrate research methods for your students as Pew has been gathering this research for years. 

Monday, October 3, 2016

Dr. Barry Marshall as an example of Type II error.

I just used this example in class and I realized that I never shared it on my blog. I really love this example of Type II error (and some other stuff, too). So here it goes.