SOLUTION: The length of human pregnancies varies normally with a mean of 266 days and a standard deviation of 16 days. What percentage of pregnancies last longer than 298 days? .3% 2.5%

Algebra ->  Probability-and-statistics -> SOLUTION: The length of human pregnancies varies normally with a mean of 266 days and a standard deviation of 16 days. What percentage of pregnancies last longer than 298 days? .3% 2.5%      Log On


   



Question 1081378: The length of human pregnancies varies normally with a mean of 266 days and a standard deviation of 16 days.
What percentage of pregnancies last longer than 298 days?
.3%
2.5%
5%
.15%

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
Probability (P) ( X > 298 ) = 1 - P ( X < 298 )
:
z-score = (298 - 266) / 16 = 2
:
P associated with z-score of 2 is 0.9772
:
******************************************
P ( X > 298 ) = 1 - 0.9772 = 0.0228 = 2.3%
******************************************
: