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SUMMARY:Compositional data analysis: A fresh approach - Professor David F
irth (University of Warwick)
DTSTART;VALUE=DATE-TIME:20230222T153000Z
DTEND;VALUE=DATE-TIME:20230222T163000Z
UID:https://talks.ox.ac.uk/talks/id/90bb5f33-8f8b-4095-baa5-2a413e5fbae5/
DESCRIPTION:The analysis of composition is a highly active area of applied
multivariate statistics\, in fields that span physical and biological sci
ence\, the social sciences and humanities. The composition of a multi-par
t entity is a fixed-sum vector representing the relative amounts of each p
art in the whole entity. Just a few examples are: in electoral politics\
, the vote shares for different political parties\; in geology\, the perce
ntages of different minerals in rock samples\; in sociology and other beha
vioural sciences\, the "time budgets" of individuals\, e.g.\, fractions of
the day that are spent sleeping\, working\, sedentary\, physically active
\, etc.\; in biology\, the relative prevalence of different microbes in th
e human gut.\n\nThe statistical literature in this area is dominated by wo
rk done in the 1980s by John Aitchison\, including the highly influential
1986 book "The Statistical Analysis of Compositional Data". The essence o
f Aitchison's approach is to transform composition vectors to a set of con
trasts among logarithms of the data\, and then work with the standard tool
s of multivariate statistics such as multivariate normal distributions and
linear models. In this talk I challenge that approach\, in terms of both
its foundational principles and some well-known practical difficulties.
A more flexible approach\, based on suitably targeted statistical models r
ather than on data-transformation\, is advocated.\nSpeakers:\nProfessor Da
vid Firth (University of Warwick)
LOCATION:24-29 St Giles' (Large Lecture Theatre\, Department of Statistics
)\, 24-29 St Giles' OX1 3LB
TZID:Europe/London
URL:https://talks.ox.ac.uk/talks/id/90bb5f33-8f8b-4095-baa5-2a413e5fbae5/
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DESCRIPTION:Talk:Compositional data analysis: A fresh approach - Professo
r David Firth (University of Warwick)
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