Question

Help with confidence interval problem (screenshot attached)

Answer 1

@ganeshie8 @tkhunny @jim_thompson5910 X)

Answer 2

Would I just simply use\[\huge \text{Z}_\alpha=\frac{\bar{x}-\mu}{\sigma}\]and solve for \(\mu\)?

Answer 3

whats the z* value for 99% confidence level ?

Answer 4

-2.33

Answer 5

Oh, so it'd just simply have to be greater than 2.33?

Answer 6

that table says \(Z^{\star} = 2.576\) ?

Answer 7

Ah. On the chart I have it's between -2.32 and -2.33

Answer 8

Make sure you're not looking at single tail sheet

Answer 9

Wouldn't it be single tailed though? Because it only mentioned that it's greater than certain value.

Answer 10

Oh, thats right !

Answer 11

I just used that \(\alpha=0.01\)

Answer 12

Ok haha I thought I was going crazy. Where can I go from here with this information?

Answer 13

find the margin of error by multiplying "standard error" and "Z*"

Answer 14

Okay, I got -0.8621

Answer 15

margin of error = 0.37*2.33 = 0.86

Answer 16

Yay X)

Answer 17

margin of error is always positive

Answer 18

Ah, okay.