flies: Medfly Data

Description

Medfly data from the Carey et al (1992) experiment. There are 1,203,646 uncensored survival times!

Usage

flies

Arguments

Format

A data frame with 19072 observations on the following 17 variables.

ageage at death in days
numfrequency count of age at death
prcurrcurrent proportion male
currentcurrent density
cohortcohort/pupal batch
sizepupal size
cagecage number
femalefemale = 1
cumulcumulative density
prcumucumulative proportion male
begininitial cage density
prbegininitial proportion mail
size4size group 4
size5size group 5
size6size group 6
size7size group 7
size8size group 8

Details

Quoting from Carey et al (1992) ``...Pupae were sorted into one of five size classes using a pupal sorter. This enabled size dimorphism to be eliminated as a potential source of sex-specific mortality differences. Approximately, 7,200 medflies (both sexes) of a given size class were maintained in each of 167 mesh covered, 15 cm by 60 cm by 90 cm aluminum cages. Adults were given a diet of sugar and water, ad libitum, and each day dead flies were removed, counted and their sex determined ...''

References

Carey, J.R., Liedo, P., Orozco, D. and Vaupel, J.W. (1992) Slowing of mortality rates at older ages in large Medfly cohorts, Science, 258, 457-61.

Koenker, R. and O. Geling (2001) Reappraising Medfly Longevity: A Quantile Regression Survival Analysis, J. Am. Stat. Assoc, 96, 458-468.

Koenker, R. and Jiaying Gu, (2013) ``Frailty, Profile Likelihood and Medfly Mortality,'' Contemporary Developments in Statistical Theory: A Festschrift for Hira Lal Koul, S.N. Lahiri, A. Schick, Ashis Sengupta, and T.N. Sriram, (eds.), Springer.