Question

The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. Find the probability of a pregnancy lasting less than 250 days.
A) 0.0066.
B) 0.0606.
C) 0.1151.
D) 0.1591.

Answer 1

Answer: C) 0.1151.

Step-by-step explanation:

Hi, to answer this question we have to apply the formula  

P =2w +2 L

Where:

P=perimeter

W= width

Hi, to answer this question we have to calculate the z score:

z= ( X-μ /σ)

Where:

X: variable

μ : mean

σ:standard deviation  

Replacing with the values given and solving:

P ( X <250) = P ( X-μ /σ < [250-268]/ 15)

P= z <-1.2

the probability(P) associated with a z-score of -1.2 is C) 0.1151. (looking in the table of z-scores)