Duncan, "Using sample survey weights in multiple regression analyses of stratified samples
," Journal of the American Statistical Association, vol.
Question 1: Is there a difference in school-wide student pass rates on English/Language Arts (ELA) assessments between an experimental group of elementary, middle, and secondary RAMP-designated schools (2007-2009) and a stratified sample
of control schools at one particular point in time (2009)?
If the variance of the observed characteristic within each stratum is smaller than that for the entire population, as is usually true, the reliability of the sample for a given size will be better or the efficiency for a given degree of reliability will be greater because we used a stratified sample
. Thus, we find stratification useful in handling heterogeneous populations.
For the above production process a QC practitioner can take either a random or stratified sample
to investigate if the process is in control.
Although there was no statistically significant difference in the indicators of fertility between linked and unlinked cases, the differential in linkage rates was considerably more pronounced in its biasing effect than the modest departures of the 1910 stratified sample
from the national public use sample of that year.
An independent research firm will select a stratified sample
of senior credit, finance and sales/marketing professionals to participate in the focus groups.
The stratified sample
includes 270 children which is not a small sample considering the resource and time expended on individually administered devices specially with very young children.
The information about daily newspapers is derived from a changed model adopted by the Newspaper Association of America that uses a stratified sample
Although it is hard to draw population conclusions from a stratified sample
of this type, two impressions struck me.
The purpose of this study was to determine if there were significant similarities or differences in problem-solving orientations and decision-making styles among a stratified sample
of rehabilitation practitioners.
We should mark the lack of any pretense to either a random or a stratified sample
. Users who might wish to perform their own statistical analyses will have to create their own sample from this data.