Sample size for a given margin of error for a mean | AP Statistics | Khan Academy

Calculate the approximate sample size required to obtain a desired margin of error in a confidence interval for a mean.

AP Statistics on Khan Academy: Meet one of our writers for AP¨_ Statistics, Jeff. A former high school teacher for 10 years in Kalamazoo, Michigan, Jeff taught Algebra 1, Geometry, Algebra 2, Introductory Statistics, and AP¨_ Statistics. Today he's hard at work creating new exercises and articles for AP¨_ Statistics.

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[kennethsumerford]

This is a good teaching video that explores sample sizes and confidence intervals.

[howitzer]

Shouldn’t the z score be 1.28 if you go by the z table

[TayToc]

I can't find the playllist this video belongs in, can someone help me with that?

[researchinstitute]

good video ... would have made the algebra a bit simpler if you first multiplied both sides by sqrt n then divide both sides by ten to avoid the reciprocals ... oh well ... to each his own ... good content anyway>

Also, good explanation of why you would not use t distribution ... essentially you would have two unknowns to solve for ... sqrt n ... and df ... but all you really need to solve for is sqrt n.

[jakeyw]

I have a TI-84 Plus and when I use the invNorm function (or any of the "DISTR" functions) I don't see all the arguments like you do. Is there a way for me to see the arguments? It is a whole lot harder to use all these functions without seeing the arguments. My initial thought is that my calculator software may be out of date but when I went on TI's website the updates available were dated back to 2011 so I don't think that is my problem. Perhaps only the TI-84 PLUS CE has this functionality?

[ehfo]

which class this video belong to? can anyone send me the link? or the complete playlist