The lengths of human pregnancies gestations can be modeled...

The lengths of human pregnancies (gestations) can be modeled by a bell-shaped distribution with mean 266 days and standard deviation 16 days. Use the Empirical Rule to answer the questions below. + If half of all pregnanices are predicted to last more than D days. What is D?

The lengths of human pregnancies (gestations) can be modeled by a bell-shaped distribution with mean 266 days and standard deviation 16 days. Additional fact: This bell-shaped distribution is actually a Normal distribution. Do not use the Empirical Rule to answer these questions, use your calculator's Normal distribution functions. (a) What percent of pregnancies are predicted to last between 240 and 270 days? (b) What percent of pregnancies are predicted to last more than 280 days? (c) What percent of pregnancies are predicted to last less than 250 days? (d) Given that the first decile (D1) of a distribution is the value that has 10% of the data less-than-or-equal-to itself, what is the first decile of the gestations? (e) Given that the third quintile (QU3) of a distribution is the value that has 40% of the data greater-than-or-equal-to itself, what is the third quintile of the gestations?

Cheng Z.