Applicants for the University of Statland take two tests, one for writing ability and the other on critical thinking, and normal
ised scores are recorded on each between 0 and 1. For a given applicant, let ???? be the score on the writing test and ???? the score on the critical thinking test. A model for the joint probability density function for the two test scores can be taken as: ????(x,y)= {x+y o for 0
