Say you have a sample of 1000 mothers and you know that the length of a woman's pregnancy is normally distributed, with a mean of 270 days and a standard deviation of 15 days. How many mothers will have their baby in the 10th month (that is, length of pregnancy above 300 days)?

A. 100
B. Can't be determined
C. 50
D. 2
E. 25

Question

Say you have a sample of 1000 mothers and you know that the length of a woman's pregnancy is normally distributed, with a mean of 270 days and a standard deviation of 15 days. How many mothers will have their baby in the 10th month (that is, length of pregnancy above 300 days)?

A. 100 
B. Can't be determined
C. 50 
D. 2
E. 25

hockeychick23 · Answer

@perl i got 25 could you check my answer please?

perl · Answer

yes i agree, because you are 2 standard deviations above the mean, and there is area of 2.5% to the right of it

hockeychick23 · Answer

ok thank you!

perl · Answer

and then multiply 2.5% by 1000 , gives you 25

hockeychick23 · Answer

ok thanks!!