Sampling stratified

Danz NP, Regal RR, Niemi GJ, Brady VJ, Hollenhorst T, Johnson LB, Host GE, Hanowski JM, Johnston CA, Brown T, Kingston J, Kelly JR. 2005. Environmentally stratified sampling design for the development of Great Lakes environmental indicators. Environ Monitor Assess 102 41-65. 

Stratified Sampling In this process dosage units are sampled at predefined intervals and representative samples collected from specifically targeted locations in the compression/hlling operations that have the greatest potential to yield extremes of drug concentration. 

Prepare a summary of the data and analysis used to correlate the stratified sampling locations with significant events in the blending process. 

This section describes sampling and testing the powder mix of demonstration and process validation batches used to support implementing the stratified sampling method described in this guidance. 

While biochemical markers of bone metabolism may be sensitive to the effects of glucocorticoids in the short term, the relation between changes in these markers and intermediate measures, such as bone mineral density, and the more important clinical outcomes of fractures, is unknown. In a random stratified sample of 3222 women in the perimenopausal age range (47-56 years), including 119 women with asthma, bone mineral density was measured to determine whether asthma was a risk factor of osteoporosis and to investigate the effect of inhaled glucocorticoids (102). The subjects had predominantly adult-onset asthma, as the age at diagnosis was over 40 years. There were 26 patients who were treated mainly with... 

The Use of Stratified Sampling of Blend and Dosage Units to Demonstrate Adequacy of Mix for Powder Blends, Blend Uniformity Working Group of Product Quality Research Institute (PQRI) available at PQRI Website (http //www. pqri.org). 

Stratified samples consist of portions obtained from identified subparts (strata) of the parent population. Within each stratum, the samples are taken randomly. 

Segregation of During compression, Remaining blend in Take stratified samples... 

Data are not random but are representative in other ways. This may mean, for example, that the data are a stratified sample applicable to the real-world situation for the assessment scenario of interest. In this case, frequentist methods can be used to make inferences for the strata that are represented by the data (e.g. particular exposed subpopulations), but not necessarily for all aspects of the scenario. However, for the components of the scenario for which the data cannot be applied, there is a lack of representative data. For example, if the available data represent one subpopulation, but not another, frequentist methods can be applied to make inferences about the former, but could lead to biased estimation of the latter. Bias correction methods, such as comparison with benchmarks, use of surrogate (analogous) data or more formal application of expert judgement, may be required for the latter. 

---