A simple random sample of size n=14 is drawn from a population that is normally distributed with a=10. the sample mean is found to be x=63. construct a 90% confidence interval about the population mean.

Question

anonymous · Answer

What does "a=10" represent?

anonymous · Answer

I hope a=10 is the standard deviation, otherwise, you can't construct the interval.

anonymous · Answer

its not a=10. idk how to do that symbol on here. it looks like an "a" but its not.

anonymous · Answer

|dw:1350770406141:dw| something like that. |dw:1350770449034:dw| and that's how X is supposed to look

anonymous · Answer

if you are using a PC, you can make the standard deviation symbol (sigma), σ, by holding down ALT and pressing 229 on the numpad.

anonymous · Answer

σ
oh sweet. i got it now. now you get the question right?

anonymous · Answer

Anyway, yes, to get the interval, you need to find the Z-score that corresponds to a 90% interval.

anonymous · Answer

I think of it like this.
|dw:1350763556077:dw|