Produce a scatterplot of state data using D3.
- Allow for the variables on the axes to change.
- Label the points with the state abbreviation.
- Use a tooltip to display data values over the plotted point.
- In our scatterplot, we compute Spearman's rank correlation coefficient
for each of the pairs of variables once at the beginning of the script and
save the results in a
Mapobject. This speeds up the rendering, since each time we switch a variable on an axis, we are only performing a table look-up and not recomputing a rank correlation (which involves two sorts and then a correlation computation).
The code for computing the correlations is from the JavaScript Statistical Library.