Incorporate Sevan's example of paralysis by analysis (week 3 discussion)

[samanthacsik]

From Sevan (week 3 discussion): "I had them try to make a figure on their own without wrangling the drought dataset. I was trying to make the point that when you have too many options, you get "paralysis by analysis". So refining your variables by subsetting is important for telling a clear story. Some of the examples the students produced were bad in a good way. It got the message across. Here's some examples."