Here is a cool newspaper article reporting on couples' premarital jitters about the marriage and the chance of divorce: http://www.sciencedaily.com/releases/2012/09/120913173324.htm, based on "Do Cold Feet Warn of Trouble Ahead? Premarital Uncertainty and Four-Year Marital Outcomes." Lavner, Justin A. Karney, Benjamin R. Bradbury, Thomas N. ; Journal of Family Psychology, Sep 3, 2012.
It is a great piece to combine conditional probability, joint probability tables, frequency tables and the law of total probability... let's see if one of my students can answer the question:
"What is the chance a couple got divorced? Don't round intermediate results, even though partial people make no sense. Report the final solution with two digit precision."
there are four ways to solve it, three of which are easier, using less of the reported detailed results. Therefore you need to amend the assignment :
You may not use the information from the following paragraph:
"Among women, 19 percent of those who reported pre-wedding doubts were divorced four years later, compared with 8 percent of those who did not report having doubts. For husbands, 14 percent who reported premarital doubts were divorced four years later, compared with 9 percent who did not report having doubts."
The beauty is that the newspaper reports rounded percentages so by asking not to round intermediate results, even knowledge of the original paper (which I assume most students can easily find electronically) does not help!
