The phrase "a three stage sample" is correct and usable in written English.
It can be used when describing a sample that is divided into three distinct stages or phases, often in research or experimental contexts.
Example: "In our study, we collected data using a three stage sample to ensure comprehensive representation of the population."
Alternatives: "a three-phase sample" or "a tri-stage sample".
All the surveys used a two stage sample based on the Ghana Population and Housing Census to produce separate estimates for key indicators for each of the ten regions in Ghana.
The survey used a two stage sample based on the 2000 Population and Housing Census to produce separate estimates for key indicators for each of the ten regions in Ghana.
In a cross-sectional study rape cases reported to the police in one province in South Africa were randomly sampled using a two stage sampling procedure.
Individual semi-structured interviews were conducted with a three stage theoretical sample of a) health (112) and administrative (66) professionals of different care levels, and b) managers of providers (42) and insurers (14).
Individual semi-structured interviews were conducted to a three stage theoretical sample: I) cases, II) providers and III) informants: insured and uninsured users (35), health professionals (51), administrative personnel (20), and providers' (18) and insurers' (10) managers.
Communities and facilities have been sampled in a three stage stratified sampling approach.
The MCS is a longitudinal study of 18 818 infants born in the UK. 15 It is based on a random two stage sample drawn from child benefit registers.
The Millennium Cohort Study is a nationally representative prospective cohort study of 18 552 families across the UK. 17 A random two stage sample of all infants born in 2000-2 and resident in the UK at 9 months was drawn from Department of Social Security Child Benefit Registers.
Briefly, a random two stage sample of all infants (both singletons and multiplets) born in England and Wales between September 2000 and August 2001, and in Scotland and Northern Ireland between November 2000 and January 2002, and who were resident in the UK at 9 months, was drawn from Department of Social Security Child Benefit Registers (to which every child is automatically entitled).
Vergese and Beig [ 57] selected the household for their study by a three stage random sampling method.
