Measures of central tendency and of dispersion

Pierre Jolicoeur
Additional contact information
Pierre Jolicoeur: University of Montreal, Department of Biological Science

Chapter Chapter 4 in Introduction to Biometry, 1999, pp 20-29 from Springer

Abstract: Abstract Most frequency and probability distributions of quantitative variates studied in biology may be interpreted using two opposite but complementary principles: the tendency of observations toward a central value on the one hand, and the dispersion of the same observations about that central value on the other hand. This state of things may be summarized algebraically by a model equation: $$ X_{h = \mu + e_h ,} $$ where h is the subscript (order number) of the h th observation in a sample, X h is the numerical value of that hth observation,μis a constant value corresponding to the central tendency, and e h is a random value which varies from each observation to the next one and accounts for dispersion. While the letter i is often used as a subscript, the letter h is preferred here because the letter i is saved for later use. Subtracting p from both members of the above model equation yields $${{e}_{h}} = \left( {{{X}_{h}} - \mu } \right)$$ which shows that the random variable e h corresponds geometrically to the distance (or deviation or deviate in statistical terminology) between the hth observation X h and the central tendency μ. Variation may be represented visually as a back-and-forth motion of an observed point X h about an equilibrium point μ when an observation is succeeded by the next one(figure 4.1.1).

Keywords: Relative Dispersion; Central Tendency; Large Standard Deviation; Skull Length; Graphical Dispersion (search for similar items in EconPapers)
Date: 1999
References: Add references at CitEc
Citations:

There are no downloads for this item, see the EconPapers FAQ for hints about obtaining it.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:sprchp:978-1-4615-4777-8_5

Ordering information: This item can be ordered from
http://www.springer.com/9781461547778

DOI: 10.1007/978-1-4615-4777-8_5

Access Statistics for this chapter

More chapters in Springer Books from Springer
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().