1. Consider the following problem
Consider the following problem. The length of human pregnancy in days, has an average of 266 days, and a standard deviation of 16 days. The distribution is normal. Let the random variable X denote the length of a human pregnancy.
Let event A be a pregnancy lasts between 266 days and 298 days.
Let event B be a pregnancy lasts between 250 days 282 days.
Let event C be a pregnancy lasts 234 days or less.
4. Calculate P(A OR B)
P(P(250 < X < 282 OR 266 < X < 298) =
P(250 < X < 298)
= P( -1 < Z < 2 ) =

2. Consider the following problem
Consider the following problem. The length of human pregnancy in days, has an average of 266 days, and a standard deviation of 16 days. The distribution is normal. Let the random variable X denote the length of a human pregnancy.
Let event A be a pregnancy lasts between 266 days and 298 days.
Let event B be a pregnancy lasts between 250 days 282 days.
Let event C be a pregnancy lasts 234 days or less.
5. Calculate P(A AND B)
P(250 < X < 282 AND 266 < X < 298) =
P(266 < X < 282)
= P(0 < Z < 1)
= Using rule.
= Using Excel
=normsdist(1) – 0.5