Tiêu đề 4. SAMPLE SIZE DETERMINATION AND.pdf ✅

PHARMD GURU Page 1 INTRODUCTION:  The question of sample size is a major consideration in the planning of experiments, but may not be answered easily from a scientific point of view.  In some situations, the choice of sample size is limited. Sample size may be dictated by official specifications, regulations, cost constraints, and/or the availability of sampling units such as patients, manufactured items, animals, and so on.  The USP content uniformity test is an example of a test in which the sample size is fixed and specified. The sample size is also specified in certain quality control sampling plans such as those described in MIL-STD-105E.  These sampling plans are used when sampling products for inspection for attributes such as product defects, missing labels, specks in tablets, or ampul leakage.  The properties of these plans have been thoroughly investigated and defined as described in the document cited above.  The properties of the plans include the chances (probability) of rejecting or accepting batches with a known proportion of rejects in the batch (sect. 12.3).  Sample-size determination in comparative clinical trials is a factor of major importance. Since very large experiments will detect very small, perhaps clinically insignificant, differences as being statistically significant, and small experiments will often find large, clinically significant differences as statistically insignificant, the choice of an appropriate sample size is critical in the design of a clinical program to demonstrate safety and efficacy.  When cost is a major factor in implementing a clinical program, the number of patients to be included in the studies may be limited by lack of funds. SAMPLE SIZE DETERMINATION AND POWER OF A STUDY

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