the experimenter waits another 15 minutes but no other customer arrives, and then she terminates the experiment. In this case, we know that the MLE. of U would have to be greater than 6, since the value of the 21st observation must be greater than 15, even though its exact value is unknown. The new M.LE. can be obtained by multiplying the likelihood function for the first 20 observations by the probability that the 21st observation is greater than 15. and finding the value of 0 that maximizes this new likelihood function(sec Exercise 15).