Question

Say you have a sample of 1,000 mothers, and you know that the length of a woman's pregnancy is normally distributed, with a mean of 270 days and a standard deviation of 15 days. How many mothers will have their baby in the 10th month (that is, length of pregnancy above 300 days)?

2

25

50

100

Can't be determined

Answer 1

You don't seem to have included any work of your own. Do better.

Answer 2

I post my questions and help other people like u guys help me

Answer 3

@jim_thompson5910

Answer 4

Im stuck on this one

Answer 5

270 days is the mean

300 days is 30 days above 270

30 = 2*15, so 300 is 2 std dev above the mean

use the empirical rule

http://www.nku.edu/~statistics/212_Using_the_Empirical_Rule.htm

Answer 6

this is a nice graphic here for empirical rule
http://www.oxfordmathcenter.com/images/notes/290-00.gif

Answer 7

@IMHERETOHELP You don't seem to be getting the idea. You've posted around 15 questions in the last three hours. I do not believe you are so stuck on all 15 that you can justify showing no work at all on all 15.

Here's the plan... Show your work. No excuses.

Answer 8

I'm doing a 50 question practice test that is worth 10 points to get me ready for the Unit Test, I am sorry for asking 15 out of 50 questions, I wont post anymore since I am not allowed to get help!

Answer 9

As far as OpenStudy is concerned, you are allowed to get help from us. If you are not allowed to get help by the instructions on your exam, then you are cheating. In any case, if you REALLY cannot show ANY work on ANY problem, you will fail the exam and prove that you are in the wrong class. Please show your work. Can I be more clear?

Answer 10

I will show my work next time I ask for help and then let u guys give me feedback then

Answer 11

Done. That is the way it should work.