PROBLEM 1 Find the probability that a clerk spends four to five minutes with a randomly selected customer. SOLUTION Find < < 5). P(4 x The gives the area to the left. cumulative distribution function (CDF) < P(X x)=1− e-m⋅x < = 0.7135 and < = 0.6321 P(x e-0.25⋅5 P(x e-0.25⋅4 5)=1− 4)=1− The probability that a postal clerk spends four to five minutes with a randomly selected customer is < < 5) = < 5) < 4) P(4 x P(x P(x − = = 0.0814 0.7135 − 0.6321 NOTE: TI-83+ and TI-84: On the home screen, enter or enter e^(-.25*4)-e^(-.25*5).
PROBLEM 1 Find the probability that a clerk spends four to five minutes with a randomly selected customer. SOLUTION Find P(4 < x < 5). The cumulative distribution function (CDF) gives the area to the left. P(X < x)=1− e-m⋅x P(x < 5)=1− e-0.25⋅5 = 0.7135 and P(x < 4)=1− e-0.25⋅4 = 0.6321 The probability that a postal clerk spends four to five minutes with a randomly selected customer is P(4 < x < 5) = P(x < 5) − P(x < 4) = 0.7135 − 0.6321 = 0.0814 NOTE: TI-83+ and TI-84: On the home screen, enter or enter e^(-.25*4)-e^(-.25*5).