Durations of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. The standard score for a pregnancy lasting 280 days is XXXXXXXXXX/15=.8 If Mary has...

Durations of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days.

The standard score for a pregnancy lasting 280 days is 280-268/15=.8

 If Mary has a pregnancy lasting 280 days, find Mary’s percentile.
Mary is in the _____________ percentile.

 What percentage of women have a pregnancy lasting longer than 259 days?
Answer: _______________ %

 What percentage of women have a pregnancy lasting less than or equal to 238 days?