# Find the smallest n possible to obtain...

• November 11th 2009, 11:02 AM
craig
Find the smallest n possible to obtain...
I have a distribution $X = N(10,4^2)$ and the following question to solve:

Quote:

Find the smallest n possible to obtain $P(9\leq X\leq 11) \geq 0.992$.
Can anyone give my any pointers as where to start with this? I can only use online statistical tables at the moment (postal strike!).

• November 11th 2009, 11:07 AM
craig
PS how do you write a tilde (~) in latex?
• November 11th 2009, 12:23 PM
ANDS!
Unfortunately, the way you described it, is the way you go about solving it. You just have to check the tables to see what interval corresponds to the percentage you are looking for.
• November 11th 2009, 07:15 PM
mr fantastic
Quote:

Originally Posted by craig
I have a distribution $X = N(10,4^2)$ and the following question to solve:

Can anyone give my any pointers as where to start with this? I can only use online statistical tables at the moment (bloody postal strike!).

Do you mean $\Pr(9 \leq {\color{red}\overline{X}} \leq 11) \geq 0.992$ ?