# Normal distr

• November 29th 2012, 02:53 AM
jacob93
Normal distr
Problem 5.21 Newbold
See image

My attempt:
1. See image2

2. Searching for it in this table Public Domain Normal Distribution Table
I find z=0.06

3. Thus, a=0.06

Correct?
• November 29th 2012, 03:06 AM
MarkFL
Re: Normal distr
a) The z-score for 0.4 is $z=\frac{0.4-0.2}{0.05}=4$, but your table only goes up to $z=3.09$ so we would use the approximation:

$P(X>4)=0$
• November 29th 2012, 03:13 AM
MarkFL
Re: Normal distr
Using numeric integration, I find:

$P(X>4)\approx0.00003167124184$
• December 4th 2012, 01:20 PM
jacob93
Re: Normal distr
Sorry, I didn't say that I was trying to do e. (But yes, in a. P ≈ 0).