A bakery makes apple pies with Golden Delicious apples. To save money, they would like to start using Red Delicious apples in their pies but want to test whether the change in the type of apple makes a difference in the taste of the pies. They ask a random sample of their customers in one day to taste test both pies. The customers do not know which pie contains which type of apple. What is the most accurate description of this study? single-blind experiment
double-blind experiment
observation
experiment

Aprisoner is trapped in a cell containing three doors. the first door leads to a tunnel that returns him to his cell after two days of travel. the second leads to a tunnel that returns him to his cell after three days of travel. the third door leads immediately to freedom. (a) assuming that the prisoner will always select doors 1, 2 and 3 with probabili- ties 0.5,0.3,0.2 (respectively), what is the expected number of days until he reaches freedom? (b) assuming that the prisoner is always equally likely to choose among those doors that he has not used, what is the expected number of days until he reaches freedom? (in this version, if the prisoner initially tries door 1, for example, then when he returns to the cell, he will now select only from doors 2 and 3.) (c) for parts (a) and (b), find the variance of the number of days until the prisoner reaches freedom. hint for part (b): define ni to be the number of additional days the prisoner spends after initially choosing door i and returning to his cell.