Question

∫1/(15√(2pi))*e^-(x-268)²/450

Answer 1

you will not find a closed form for the "anti derivative" of
\[e^{-(x-268)^2}\]

Answer 2

\[\int\limits_{250}^{280}1/15\sqrt{2\pi}\times e ^-{\left(x-268\right)^{2}/450 dx}\]

Answer 3

It's tricky to type this up with the equation formulas available. Anyway, it's basically a probability problem with a mean and SD.

Answer 4

yes so i think you are going to have to use a table of some kind because you are not going to find the anti derivative of this beast

Answer 5

Problem is the lecturer seems to expect us to be able to integrate this because no tables have been recommended or given. Brand new to probabilities.

Answer 6

There is no antiderivative in terms of elementary functions so you will need to use a table or calculator/computer to compute this integral

Answer 7

Ok, the lecturer gave us these problems over the weekend without much instruction, so how do I use a calculator to solve this? Do I plug in the limits to get a numeric value and then integrate everything? Doesn't seem correct.

Answer 8

what type of calculator do you have?

Answer 9

Just a plain scientific one

Answer 10

does it have a numerical integration function on it?

Answer 11

I doubt it; I don't see any integral symbols. What should I look for?

Answer 12

i get .788144601395 on my calculator

Answer 13

\[\int\limits_{50}^{280}\frac{1}{15\sqrt{2\pi}}e^{-\frac{(x-268)^2}{450}}dx\approx.788144601395\]

Answer 14

That sounds correct, given that the question asked, "What percentage of pregnancies are considered full term?" 79% sounds about right. How did you get that answer? What do I use on my calculator?

Answer 15

I used my Ti-nspire CX CAS

Answer 16

What? Ok, definitely don't have those symbols on my calculator. Not sure why the lecturer gave us this problem, but thanks for your help, anyway.

Answer 17

I have 3 scientific calculators that can do numerical integrals...what type of scientific calculator do you have?

Answer 18

Oh, sorry, you were referring to the actual name of the calculator. Mine is TI-30XA

Answer 19

ti36x pro
casio fx-115es
sharp EL-W516x
all can do numerical integrals

Answer 20

the ti-30 can't do numerical integral

Answer 21

I have a ti-30xs

Answer 22

I am a calculator whore...I have 11 or 12 of them

Answer 23

Alright, that solves that problem. Provided I know that one needs a calculator in order to solve this, I'm relieved. (I like your comment about your affinity for calculators :-))