* A stratified sample
of 520 students was invited to participate in the study.
As stated above, the stratified sample
contains features [mathematical expression not reproducible].
Is there a difference in school-wide student pass rates on Math 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)?
(3) Estimates are from Hodges and others (1984) because the original plot selection was based on a stratified sample
with optimum allocation of effort which would cause a simple random sample analysis to be biased.
Well done to Kelly Gardner from Newcastle who correctly worked out that 195 people from Tyneside would be needed in the stratified sample
GAO analyzed a stratified sample
of FDA's 3R incentives files, 3R data provided by HHS, HHS's 3R policy and FDA's guidance, and interviewed HHS, FDA, and OPM senior officials.
In spring 2008, LRS staff visited the web sites of nearly 600 public libraries in the United States, searching for the existence of certain web technologies, including technologies defined as "Web 2.0." The web sites that were examined were drawn from a stratified sample
of public libraries in the United States, with approximately equal numbers of libraries included from each of five different population ranges.
Use of a stratified sample
allows you to control the proportion of the sample being drawn from each apartment unit type, thereby controlling for unit-mix sampling error.
A random stratified sample
of doctors and nurses (N=150) was selected from the list of 2 200 health professionals employed at the hospital.
The sampling method initially employed a non-probability sampling scheme that evolved to a second data tier using a random stratified sample
. The data are perhaps less representative than presumed; yet the insight afforded through in-depth and longitudinal interviewing is substantial.
Further research may properly address these limitations by enlarging the sample, according to criteria of statistical representativeness, and by opting for a stratified sample
, by either years of practice, or practice in the public/ private sector, or average yearly earnings.
The NAEP is only administered to a stratified sample