# Math Help - Find the smallest n possible to obtain...

1. ## Find the smallest n possible to obtain...

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

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!).

2. PS how do you write a tilde (~) in latex?

3. 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.

4. 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 $\Pr(9 \leq {\color{red}\overline{X}} \leq 11) \geq 0.992$ ?