OpenIntroStat / openintro-statistics

📚 An open-source textbook written at the college level. OpenIntro also offers a second college-level intro stat textbook and also a high school variant.
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Ch 5: Definition of standard error #11

Closed mine-cetinkaya-rundel closed 5 years ago

mine-cetinkaya-rundel commented 5 years ago

https://github.com/OpenIntroOrg/openintro-statistics/blob/b7e661929a25ca0f7fb530139e1c5aa015f1f459/ch_foundations_for_inf/TeX/ch_foundations_for_inf.tex#L212-L218

A more accurate definition would be that the variability of the sample statistic is called the standard error when calculated using sample statistics, since it's called the standard deviation if calculated using true population parameters.

Not sure if going into that distinction is worthwhile here, since the latter case rarely happens, but the definition here makes it sound like the variability of a sample statistic is always called standard error, which is not accurate.

Relatedly, the formula below is not correct:

https://github.com/OpenIntroOrg/openintro-statistics/blob/b7e661929a25ca0f7fb530139e1c5aa015f1f459/ch_foundations_for_inf/TeX/ch_foundations_for_inf.tex#L284

If using p, this should be called sigma. If using p-hat, it would be called SE.

I would suggest the following changes to address these two concerns:

mine-cetinkaya-rundel commented 5 years ago

If this change is implemented it will also affect the following line,

https://github.com/OpenIntroOrg/openintro-statistics/blob/ecad440aa2922a5dd8a4fd7eaa9cf577e26fd119/ch_foundations_for_inf/TeX/ch_foundations_for_inf.tex#L952-L954

where we could do away with the approximation since by definition SE is an approximation, and say

SE = \sqrt{\frac{\wsjebolapollprop{} (1 - \wsjebolapollprop{})}{\wsjebolapollsize{}}} 
DavidDiez commented 5 years ago

Let's catch up on this in our next meeting; I've added a note there so this doesn't get lost.