Wordsmith Talk |
About Us | What's New | Search | Site Map | Contact Us | |||
Register Log In Wordsmith.org Forums General Topics Q&A about words quartile variations
Previous Thread
Next Thread
Print Thread
There seems to be a systematic ambiguity. The quartiles are the three values that divide a probability distribution into four parts; but loosely, "quartile" is also used for any one of the four parts so created.
The only terms I've seen are quartile, decile, and percentile, and I think these are all subject to the same ambiguity. People talk of something being in the top percentile, meaning it's in the top 1%. Strictly this is above the top percentile, which is the 99th percentile.
If n is an integer, an n-ile is a value that divides the data into n equal parts, so there are n - 1 n-iles altogether. The first n-ile separates the lower 1/n from the remaining (n - 1)/n. So the first quartile separates the lower quarter from the upper three-quarters, the middle quartile separates the upper and lower halves, and the upper quartile separates the lower three-quarters from the upper quarter.
Those quarters are also loosely referred to as quartiles, under the natural (mis)apprehension that there must be four quartiles.
If q is a proportion 0 < q < 1, the q-quantile is the point such that the amount of data under it is q. So the first quartile is the 0.25-quantile.
As quartus is a Latin ordinal, and as the old month names were Quintilis and Sextilis, probably "tertile" is a good name for the two points dividing data into three.
http://www.riskglossary.com/articles/quantile.htm
Entire Thread Subject Posted By Posted quartile variations jennieho 11/27/03 10:42 AM Re: quartile variations wwh 11/27/03 01:38 PM Re: quartile variations stales 11/28/03 01:05 AM quantiles Jenet 11/28/03 06:56 AM Re: quantiles Buffalo Shrdlu 11/28/03 11:51 AM Re: quantiles Faldage 11/28/03 12:59 PM Re: quantiles Buffalo Shrdlu 11/28/03 01:04 PM Re: quantiles Faldage 11/28/03 01:07 PM Re: quantiles Buffalo Shrdlu 11/28/03 01:24 PM Re: quartiles Jackie 11/28/03 07:54 PM Re: quartiles Buffalo Shrdlu 11/28/03 08:58 PM circiles Jenet 11/28/03 11:48 PM Re: circiles Jackie 11/29/03 02:37 AM more -iles wofahulicodoc 12/01/03 12:00 AM
Moderated by Jackie
Link Copied to Clipboard
Forum Statistics Forums16Topics13,913Posts229,342Members9,182 Most Online3,341
Dec 9th, 2011
Newest Members Ineffable, ddrinnan, TRIALNERRA, befuddledmind, KILL_YOUR_SUV
9,182 Registered Users
Who's Online Now 0 members (), 491 guests, and 1 robot. Key: Admin, Global Mod, Mod
Top Posters(30 Days) A C Bowden 20ddrinnan 1
Top Posters wwh 13,858Faldage 13,803Jackie 11,613wofahulicodoc 10,546tsuwm 10,542LukeJavan8 9,917Buffalo Shrdlu 7,210AnnaStrophic 6,511Wordwind 6,296of troy 5,400
Forum Rules · Mark All Read Contact Us · Forum Help · Wordsmith.org