# Thread: A random sample of size 36 is selected...?

1. ## A random sample of size 36 is selected...?

A random sample of size 36 is selected from a population whose mean is 60 and standard deviation is 6. Calculate the probabillity that:
59 ≤ X ≤ 61

2. Originally Posted by Mitchell
A random sample of size 36 is selected from a population whose mean is 60 and standard deviation is 6. Calculate the probabillity that:
59 ≤ X ≤ 61
I assume X is the random variable 'mean of the sample'. Read this: Sampling distribution - Wikipedia, the free encyclopedia

3. Yeah it is. I meant to put x-bar but it showed up as just X for some reason. But, I'm still not sure what I'm supposed to do here. Do I just find the standard error?

4. Originally Posted by Mitchell
Yeah it is. I meant to put x-bar but it showed up as just X for some reason. But, I'm still not sure what I'm supposed to do here. Do I just find the standard error?
Did you read the link? What did it say about the distribution that $\overline{X}$ follows? Where are you still stuck?