Assume that the duration of human pregnancies can be described by a normal model with mean 266 days and standard deviation 16 days.
what percentage of pregnancies should last between 270 and 280 days?

21.05%

Step-by-step explanation:

First find the z-score  for both 270 and 280 days of pregnancy and their equivalent percentile in the normal distribution.

For X = 270 days:

A z-score of 0.25 corresponds to the 59.871 th percentile

Therefore, 59.871% of pregnancies should last less than 270 days.

For X = 280 days:

A z-score of 0.875 corresponds to the 80.921 th percentile

100 - 80.921 = 19.079

Therefore, 19.079% of pregnancies should last more than 270 days.

The percentage of pregnancies lasting  between 270 and 280 days (P) is given by:

P=100 -19.079-59.871

P=21.05%

points are handed out whenever you post answers.

brainliest answers are handed out by the person asking the question, so whether your answer is picked depends entirely on whether the asker bothers to pick

if you're asking about your rank, it depends on having a certain number of points and a certain number of brainliest answers. for example, at the time of this writing, i have 44338 points out of 15000 needed for the next (nearly triple the requirement! ) but i only have 24 out of 50 required brainliest answers. this number decays, meaning after a certain amount of time (i think about a month), the total number of brainliest answers you've earned doesn't count toward this total. (i've been stuck at the same rank for a long

the lesson to learn here is that you shouldn't worry about points or rank. chances are, no matter how good an answer you may provide, your efforts will go mostly unnoticed unless you focus on the newest/most active questions that get posted.

in mathematics, a constraint is a condition of an optimization problem that the solution must satisfy. there are several types of constraints—primarily equality constraints, inequality constraints, and integer constraints. the set of candidate solutions that satisfy all constraints is called the feasible set.

hoped i'm right lol