Neyslukönnun - 01.10.1997, Síða 88

86
Neyslukönnun 1995
Appendix 2
Calculation of weightings
Sampling probability
If n is the probability of household i of household type h to be selected in the sample, then
W)
where
N is the number of family identity numbers in the population where age is 18-74 years,
zf is number of household members aged 18-74 years in household i of household type h who have their own family identity number.
Participation probability
Probability of participation p for household h is
h
Ph
mh 1
i=1 nh(i)
i'=l
1
Kh(i)
i=l f'h(i)
where
m is number of households of household type h that participated in the HBS
n * is number of households of household type h in the sample
h
Finally, a composite weight was created incorporating different probabilities for both
....................tt r Xh(Í)
selection and participation =
nh(i)Ph
where
x is number of household members drawn in the sample in household i of household type h,
jt,l> is selection probability of household i of household type h,
ph<“ is participation probability of households of household type h.
h
This weight was used to calculate total expenditures by categories
5 mh
h=\ i= 1
where
Y is expenditure in certain categories for household i of household type h.
h(i)
There are 5 household types (h= 1,___,5).