The lengths of telephone calls form a normal distribution with a mean length of 8.0 min and a standard deviation of 2.5 min. The probability that a telephone call selected at random will last more than 15.5 min is most nearly
a.0.0013
b.0.0026
c.0.2600
d.0.9987

The answer is a.) 0.0013

Step-by-step explanation:

Telephone calls of a normal distribution have  a mean, = 8 min and a standard deviation, = 2.5 min for the lengths of the call.

A randomly selected telephone call  whose probability that the call will last more than 15.5 min will be given by

p ( x > 15.5)

The Z test statistic will Z   = .

Therefore we have to find p(Z > 3).

p(Z >3)  1 - p( Z < 3) =  1 - 0.9987 = 0.0013.

From the Z table we can find the value of p( Z < 3) to be 0.9987

The answer is a.) 0.0013

for the first question it would be the second answer for the second question it would be the third answer and for the third question it would be the first answer

step-by-step explanation: