Stata Technical Bulletin
Figure 2. Schematic illustration of a three-generation family.
Generation 1
Generation 2
Figure 1. Schematic illustration of a two-generation family.
Syntax
simuped2 #Age1 #Std1 #Age2 #Std2 [, r eps(#) saving filename) alle(#) sib(#) ]
simuped3 #Age1 #Std1 #Age2 #Std2 #Age3 #Std3 [. E®ps(#) saving (filename) alle(#) sib(#) si3(#) ]
Description
simuped2 and simuped3 are immediate commands used for generating two- and three-generation family data, respectively.
For each person in a family, the sex is generated by a probability of 0.5. The age of a person is generated according to a normal
distribution, with means #Ageb #Age2, and #Age3 for the first, second, and third generations. The standard deviations of the ages
are given by #smi, #Std2, and #St<β, respectively.
The number of siblings in a generation is a random number, distributed according to a Poisson distribution. The mean sizes
of the siblings in the second- and third-generation are given by sib(#) and si3(#), respectively.
Hardy-Weinberg equilibrium is assumed for the genotypic distribution of people in the first generation (see, for example,
Elandt-Johnson 1971). The allele frequency of a biallelic locus A is given by the argument alIe ##), denoted as p. The frequencies
of genotypes AA, Aa and aa in the first generation are given by p2, 2p(l — p) and (1 — p)2, respectively. The genotype of
a person in the second- and third-generation is generated according to the Mendelian inheritance, that is, a person inherits the
allele A from the father (or mother) with probability 0.5.
The simulated family data are saved in a file specified by savingfilename), and the number of replications is specified by
reps (#).
Options
reps (#) specifies the number of simulated families. The default value is 100.
savingfilename) specifies the file into which the simulated data are saved. The default file name is temp.dta.
allé (#) specifies the allele frequency of a biallelic locus A. The default value is 0.1.
sib(#) specifies the mean number of siblings in the second generation. The default value is 3.
si3(#) specifies the mean number of siblings in the third generation. It is only used in simuped3. The default value is 3.
Remarks
simuped2 and simuped3 simulate the basic quantities of a person, such as age, sex, and genotype, which are useful in
genetic epidemiology research. Further quantities of interest, such as the disease status of a person, can be simulated based
on these basic family data. However, it sometimes requires specific models for the affect of a disease and the model of the
natural mortality of a person. We do not include the disease status in the programs because that would not make simuped2 and
simuped3 of as general use.
More intriguing information
1. The name is absent2. Fiscal Sustainability Across Government Tiers
3. Ability grouping in the secondary school: attitudes of teachers of practically based subjects
4. A Study of Adult 'Non-Singers' In Newfoundland
5. Land Police in Mozambique: Future Perspectives
6. The name is absent
7. Non-farm businesses local economic integration level: the case of six Portuguese small and medium-sized Markettowns• - a sector approach
8. The name is absent
9. The Role of Trait Emotional Intelligence (El) in the Workplace.
10. The Prohibition of the Proposed Springer-ProSiebenSat.1-Merger: How much Economics in German Merger Control?