Statistics help please.

[emiizladii]

A standard placement test has a mean of 115 and a standard deviation of ? = 10. Determine the minimum sample size if we want to be 95% certain that we are within 3 points of the true mean.

 

[galactus]

This isn't anything fancy. Just use the formula $\displaystyle n=\left(\frac{z\cdot {\sigma}}{E}\right)^{2}$

Notice where this formula comes from?. It comes from the confidence interval formula solved for n:

$\displaystyle E=z\cdot\frac{\sigma}{\sqrt{n}}$

$\displaystyle E\sqrt{n}=z{\sigma}$

$\displaystyle \sqrt{n}=\frac{z\sigma}{E}$

$\displaystyle n=\left(\frac{z\sigma}{E}\right)^{2}$

Plug in your givens remembering that the z score for 95% is 1.96. Round up your solution.

 

[Denis]

> Your mom is so fat, when she walks she sheds vortices so large that Modern Synoptic Scale models include her as a factor.

Your mom is so fat she has to iron her panties in the driveway.

 

[galactus]

Your mom is so fat she has to iron her panties in the driveway.

I put those silly things up there because I thought they were different and off the wall compared to most jokes.

 

[melius bd]

is this a real site .. or its a site for games

 

[Deleted member 4993]

is this a real site .. or its a site for games

What makes you think that this is a site for games??? What games????