A psychologist has developed a test for school children that is supposed to identify who will commit violent crimes during adolescence and young adulthood. In one school 10 percent of the 200 children tested show a positive result, indicating criminal potential. Half of these children do indeed go on to commit violent crimes, whereas only 5 percent of those who tested negative do so.
1. What is the observed agreement between the test and the result?
2. What is the expected agreement between the test and the result?
3. Calculate the kappa statistic to measure how well the test result agrees with the outcome.