Editing Standard deviation (section)

===Standard deviation of average height for adult men===
If the population of interest is approximately normally distributed, the standard deviation provides information on the proportion of observations above or below certain values. For example, the [[Average human height|average height for adult men]] in the [[United States]] is about {{tooltip|69&nbsp;inches|{{convert|69|inches|cm ftin|0|disp=out}}}},<ref>{{citation |url=https://www.cdc.gov/nchs/data/series/sr_03/sr03-046-508.pdf |title=Anthropometric Reference Data for Children and Adults: United States, 2015–2018 |series=National Center for Health Statistics: Vital and Health Statistics |date=January 2021 |publisher=Centers for Disease Control and Prevention |volume=3 |number=46 |page=16, Table 12}}</ref> with a standard deviation of around {{tooltip|3&nbsp;inches|{{convert|3|inches|cm|disp=out}}}}. This means that most men (about 68%, assuming a [[normal distribution]]) have a height within 3&nbsp;inches of the mean ({{tooltip|66–72&nbsp;inches|{{convert|66–72|inches|cm ftin|0|disp=out}}}}){{snd}}one standard deviation{{snd}}and almost all men (about 95%) have a height within {{tooltip|6&nbsp;inches|{{convert|6|inches|cm|disp=out}}}} of the mean ({{tooltip|63–75&nbsp;inches|{{convert|63–75|inches|cm ftin|0|disp=out}}}}){{snd}}two standard deviations. If the standard deviation were zero, then all men would share an identical height of 69&nbsp;inches. Three standard deviations account for 99.73% of the sample population being studied, assuming the distribution is [[Normal distribution|normal]] or bell-shaped (see the [[68–95–99.7 rule]], or the ''empirical rule,'' for more information).