Can anyone advise a good transformation for this data below to produce a normalised distribution? Many thanks, Georgina No. of eggs on mosquito gut: 1 12 1 12 6 17 54 1 12 2 22 27 1 27 1 1 6 24 10 54 12 5 27 68 1 4 6 27 1 1 1 1 68 1 7 1 10 5 4 1 7 9 3 19 22 10 4 PhD Student Division of Infection and Immunity B5-29, GBRC 120 University Place Glasgow G12 8TA Tel: 0141 330 5650
Transformation for -ve binomial data
2 messages · Georgina Sarah Humphreys, Ben Bolker
Georgina Sarah Humphreys <g.humphreys.1 <at> research.gla.ac.uk> writes:
Can anyone advise a good transformation for this data below to produce a
normalised distribution?
Many thanks, Georgina
Depending on how "normal" you want it to be, this may be impossible because about a third of your data set (14/47) has the same value (1). There's no transformation that can spread out a peak consisting of identical values. d <- c(1,12,1,12,6,17,54,1,12,2,22,27,1,27,1, 1,6,24,10,54,12,5,27,68,1,4,6,27, 1,1,1,1,68,1,7,1,10,5,4,1,7,9,3,19,22,10,4) table(d)
table(d)
d 1 2 3 4 5 6 7 9 10 12 17 19 22 24 27 54 68 14 1 1 3 2 3 2 1 3 4 1 1 2 1 4 2 2 Naively, the Box-Cox transformation says you should be using a log transformation (lambda=0) library(MASS) boxcox(d~1) good luck, Ben Bolker