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

y=mx+b

step-by-step explanation:

m slope, b y-intercept

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.