Question

The lengths of human pregnancies are normally distributed with a mean of 268 day & a standard deviation of 15 days. What is the probability that a pregnancy last at least 300 days?

Answer 1

There is a low probability most likely 0.9

Answer 2

Explanation:

The lengths of human pregnancies are normally distributed with a mean of 268 day and a standard deviation of 15 days

From the information given,

mean, u =268

standard deviation, s = 15

x is number of days

For normal distribution,

z = (x-u)/s

Probability of x greater than or equal to 300 will be 1 - probability of x lesser than 300

z = (300-268)/15 =32/15 = 2.13

Looking at the normal distribution table, the value is 0.98341

Probability of x greater than or equal to 300 will be 1 -0.98341

= 0.01659