Lesson 1 Notes
The hardest part of this lesson will be incorporating StatCrunch for the first time. Students have access to StatCrunch in one of two ways (1) Either they purchased MyStatLab and they are granted automatic access to StatCrunch or (2) They purchased StatCrunch separately.
To read it into StatCrunch, go to the MyStatCrunch tab on the StatCrunch website (logging in should get you there) and you will see a section that reads “My Data”:
The easiest thing for them to do is save the cholera data to their hard drive and then click on the appropriate link in StatCruch My Data. If they are successful, they should see
To compute a mean, choose the menu bar “STAT”, then choose “SUMMARY STATS” and then choose “COLUMN”
The students will be asked to compute the mean for both the lon and lat variables. This will be used in mapping. They might want to note or write down the values. They just need to identify the variable and choose “MEAN” otherwise they will get many more values than they need for this exercise.
On mapping, in StatCrunch, mapping is just a graph. It's the last option of the graphing menu, choose “Google Map”. They will need to use the variable LOCATION and not lat and lon as the StatCrunch interface with Google needs a single value. If they do it correctly, a map should result. The only option I would worry about is making sure the plot DOES NOT cluster the points. Annotation is optional, I annotated it with the count of Cholera deaths but it isn't required.
Here is the hard part – I'd like them to add the mean lat and mean lon to the map and color it red. This is where they need their means and they need to add this information to the last part of the input. If you look at the highlighted input box (blue emphasis). The last line reads “your mean lat, your mean lon | #ff0000|count: 0” this needs to be changed:
So if they substiute something like “51.513416, -0.13641526 | #ff0000|count: 0” (no quotes) they will get the correct result, a red marker should pop up in the middle of their points after they click “plot locations” at the bottom of the map results.
Last thing is to use street view to find the pump (it's not real, it's a memorial). They just need to drag the little man to the red marker and release:
The student might need to spin around in streetview to see the pump, but if they computed the means correctly and plotted, it should work. This is basically repeating Dr. Snow's analysis of Cholera deaths. He mapped the deaths, located the central point and looked around and saw the Broad Street pump. From that, he took samples of the water and discovered Cholera.
The remainder of the lesson is much more straightforward and you should be OK, but let me know, give it try before teaching on Tuesday (you can show them how to do it, I leave it to you, you can also show them this page if they are just lost…)