The math help thread

I have to look in my stats book but I think for confidence interval it's

sample mean/average "+ or -" sigma/SQRT(n) * Z(alpha)

Sample mean/average is "u" or "X bar"

Sigma in this problem is 0.2

SQRT(n) is square root of sample

Z(alpha) relates to 95%, in this case it's about 1.96 if i'm not mistaken

So just solve for 'n' i.e.

sigma/SQRT(n) * 1.96 = 0.15

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I might have some things wrong because I don't wanna dig up my notes, but it's just a formula somewhere.

Thanks, sir. I know your answer is right because I went to the office hours earlier today and had it explained to me more clearly

I got the 95% confidence mistaken since I directly took 95% from the normal table when I should have taken half of 100%-95%, which is 1.96. *Understands the material now *