Surveys sample size

Extensive testing was also carried out to assess future hazards for human habitation and residential use of the area. This testing was carried out in an extensive program funded by EPA In 1980-81 after remedial drainage construction work at the Canal was complete (O. All of the survey design and technical laboratory problems described above were encountered in this program. Despite extensive efforts to meet requirements for sample size and distribution, to provide for adequate control sampling away from the Canal area, and... 

The target number of commodity samples to be obtained in the OPMBS was 500, as determined using statistical techniques. A sample size of 500 provided at least 95% confidence that the 99th percentile of the population of residues was less than the maximum residue value observed in the survey. In other words, a sample size of 500 was necessary to estimate the upper limit of the 95% confidence interval around the 99th percentile of the population of residues. 

Huan et al. [41] measured the behavior of a small fluidized bed consisting of 45-80 mustard seeds in a small-bore vertical magnet. The small sample size allowed short pulses, and spatial distribution of collision correlation times and granular temperature were measured directly and compared with the hydrodynamic theory of Garzo and Dufty [42], This paper [41] contains an excellent survey of previous experiments on fluidized beds. 

For several years, we have conducted national surveys among representative samples of college graduates who are registered to vote. We chose to examine this population segment because it is politically influential. The sample size in the most recent survey, in March 1999, was 500. 

However, since the data used in this study are subject to the limitations and uncertainties cited above, the results of this analysis represent only a very rough approximation of the national frequency distribution of indoor radon levels. EPA s national survey will seek to more accurately characterize this distribution through use of a larger sample size, a statistically based survey design, and consistent, quality assured sample collection and measurement procedures. 

The sample size of the survey will depend primarily on the need to accurately estimate the upper percentiles of the national distribution and the number of subgroup populations for which frequency distributions are needed and the level of accuracy needed for these distributions (Cox et el., 1985). 

Prozac, 259 Pseudomonas, 142 Psychiatric drugs, 177 Public attitudes, 3-26 Public attitudes survey key findings of, 7-25 methodology for, 5-7 questions for, 7 sample size for, 6 sampling frame for, 6 survey instrument for, 6 telephone interviews for, 6 Public databases, 36, 39 Public education, increase in, 26 Public health genetics, 138 Public health genetics in, 150 protecting, 108, 217... 

Freiman JA, Chalmers TC, Smith HJ, et al. The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 negative trials. N Engl J of Med 1978 299 690-4. 

To begin, the author cites evidence that Americans are trying to get fit and beat stress. First of all, America is a large country, so it is illogical to make the leap that because unnamed studies show that Americans want to get fit, Smallville citizens are also looking to improve their health and fitness. Because the studies cited are unnamed, the reader cannot assume their validity—the reader doesn t know the sample size, the institutions that conducted the surveys, or what kind of fitness and stress-busting these polled Americans want. 

As shown in Tables 5-2 and 5-3, the data on each group include survey period, geometric mean, population sample size, and the biomarker concentration at the 50th, 75th, 90th, and 95th percentiles of the population distribution. 

Sample Preparation. Herrin No.6 (Illinois No.6) and Indiana No.5 (Illinois No.5) coals obtained from the Illinois Geological Survey Sample Bank were used in this study. The whole coals were split into four fractions each of which was placed in a sealed, 5-gallon drum. The fourth fraction was ground to minus 200 mesh and then introduced into a nitrogen gas powered (100 psi) Sturtevant fluid energy mill. In this device the coal particle size is reduced to the micron level by impaction between coal particles themselves and with the impaction chamber walls. Proximate and elemental data for these micronized coals are reported in Table I. 

Suspected risk factors for obsessive-compulsive disorder were investigated in a prospective epidemiological study, using data from the Epidemiologic Catchment Area surveys (1980-1984) (176). Users of both cocaine and marijuana were at increased risk of obsessive-compulsive disorder compared with non-users of illicit drugs, but cocaine use alone was not associated with an increased risk, within the limited sample size. 

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