I've tried using the formula n = (z-crit*standard deviation/standard error)^2 but it didn't seem to work. Not sure what else I can try? Would working backwards from the formula:

*work?*

**point estimate +/- z-crit * standard error**Thanks in advance!

- Thread starter nathinho
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I've tried using the formula n = (z-crit*standard deviation/standard error)^2 but it didn't seem to work. Not sure what else I can try? Would working backwards from the formula:

Thanks in advance!

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- Apr 12, 2005

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- 10,098

Yes, and that should lead you to \(\displaystyle n = \dfrac{s^{2}t^{2}}{d^{2}}\)

I've tried using the formula n = (z-crit*standard deviation/standard error)^2 but it didn't seem to work. Not sure what else I can try? Would working backwards from the formula:work?point estimate +/- z-crit * standard error

Thanks in advance!

- Joined
- Mar 16, 2016

- Messages
- 1,434

What is the point estimate? What is the standard error? What is the z-crit?