# Need help with Statistics

1. Jun 6, 2004

### bluebear

Hello,
I'm having trouble with this one question on my review sheet (yikes, and I have a chapter test on Statistics tomorrow!). The question is: What is the area under the standard normal curve that is within 1.5 standard deviations of z=1?

a) 0.2838 b) 0.3050 c) 0.5637 d) 0.6853 e) 0.7714

The answer is D, but I don't know how to get that answer. Anyway, if anyone can help, that'll be GREAT!! Thanks so much!!

2. Jun 6, 2004

### Gokul43201

Staff Emeritus
You can't really calculate this with paper and pen. However, there are tables that give you the area between different intervals. I'm not sure what the tables are referred to as, but you could try Googling. Also see Gaussian Integral and error function.

Note : the shape of the std. normal curve is the gaussian function :

$$f(x)= {\frac {1} {\sigma \sqrt{2\pi}} e^{-x^2/{2{\sigma}^2}}$$

Last edited: Jun 6, 2004
3. Jun 6, 2004

### bluebear

Thanks!

Thanks for helping! I've finally figured out the answer! =) :surprise: