minor fixes to the Compas example

[LiFaytheGoblin]

I intent to fix #79 #80 #81

• I switched the variable names that got mixed up
• I reworded "equally likely to predict" to "equally likely to incorrectly predict"
• I reworded "We can see from the longer bars" to "We can see from the absolute number of occurances given next to a bar"

[LiFaytheGoblin]

Thanks for the feedback @lorenh516 and you're welcome. See my updated changes.