Mean

Dinastatistik,méan(rata-rata) mibanda dua harti:
Sampel méan biasa dipaké keurestimatorticentral tendencysaperti populasi méan. Sanajan kitu, éstimator séjén ogé dipaké. Contona,medianéstimator nu leuwihrobustkeur central tendency tinimbang sampel méan.
Keur nilai-réalvariabel acakX, méan nyaétanilai ekspektasiX.
Lamun ekspektsi euweuh, variabel random teu mibanda méan.
Keurruntuyan data, méan ngan sakadar jumlah sakabéh observasi dibagi ku lobana observasi. 
Keur ngajelaskeunkomunaltina susuna data, geus ilahar dipakésimpangan baku, nu ngajelaskeun sabaraha béda tina observasi.
Simpangan baku mangrupa akar kuadrat tinaaverageatawa deviasi kuadrat tina méan.
Méan mangrupa nilai unik ngeunaan jumlah kuadrat deviasi nu minimum.
Lamun ngitung jumlah kuadrat deviasi tina ukurancentral tendencyséjén, bakal leuwih gedé tinimbang keur méan.
Ieu nerangkeun kunaon simpangan baku sarta méan ilahar dipaké babarengan dina laporan statistik.
Alternatip keur ngukur dispersi nyaéta simpangan méan, sarua jeungaveragesimpangan mutlaktina méan.  Ieu kurang sensitip keuroutlier, tapi kurang nurut waktu kombinasi susunan data.
Nilai méan tina fungsi,f(x){\displaystyle f(x)}, dina interval,a<x<b{\displaystyle a<x<b}, bisa diitung (ngagunakeun prosés limit dina definisi susunan data) saperti:
Catetan, teu sakabéhprobability distributionmibanda méan atawavarian-  keur conto temposebaran Cauchy.
Di handap mangrupa kasimpulan tina sababaraha metoa keur ngitung méan tina susunan wilangann.Tempotable of mathematical symbolskeur nerangkeun simbol nu dipaké.
Thearithmetic meanis the "standard" average, often simply called the "mean". It is used for many purposes  but also oftenabusedby incorrectly using it to describeskeweddistributions, with highly misléading results. The classic example is average income - using the arithmetic méan makes it appéar to be much higher than is in fact the case. Consider the scores {1, 2, 2, 2, 3, 9}. The arithmetic méan is 3.16, but five out of six scores are below this!
Thegeometric meanis an average which is useful for sets of numbers which are interpreted according to their product and not their sum (as is the case with the arithmetic méan). For example rates of growth.
Theharmonic meanis an average which is useful for sets of numbers which are defined in relation to someunit, for examplespeed(distance per unit of time).
Thegeneralized meanis an abstraction of the Arithmetic, Géometric and Harmonic Méans.
By choosing the appropriate value for the paramétermwe can get the arithmetic méan (m= 1), the géometric méan (m-> 0) or the harmonic méan (m= -1)
This could be generalised further as
and again a suitable choice of an invertible f(x) will give the arithmetic méan with f(x)=x, the géometric méan with  f(x)=log(x), and the harmonic méan with f(x)=1/x.
Theweighted meanis used, if one wants to combine average values from samples of the same population with different sample sizes:
The weightswi{\displaystyle w_{i}}represent the bounds of the partial sample. In other applications they represent a méasure for the reliability of the influence upon the méan by respective values.
Sometimes a set of numbers (thedata) might be contaminated by inaccurate outliers, i.e. values which are much too low or much too high.  In this case one can use atruncated mean. It involves discarding given parts of the data at the top or the bottom end, typically an equal amount at éach end, and then taking the arithmetic méan of the remaining data.  The number of values removed is indicated as a percentage of total number of values.
Theinterquartile meanis a specific example of a truncated méan. It is simply the arithmetic méan after removing the lowest and the highest quarter of values.
assuming the values have been ordered.