The precision of parameters estimation are determined by the sample size and the sampling design used in a study. Due to such practical constraints as the budget and manpower, most large-scale educational studies would not adopt the simple random sampling design. TIMSS 2007 used a two-stage stratified cluster sampling design. In the first stage, about 150 schools were selected according to some...

in this research, a new control policy for the acceptance sampling problem is introduced. decision is made based on the number of defectives items in an inspected batch. the objective of the model is to find a constant control level that minimizes the total costs, including the cost of rejecting the batch, the cost of inspection and the cost of defective items. the optimization is performed by ...

in zero acceptance number sampling plans, the sample items of an incoming lot are inspected one by one. the proposed method in this research follows these rules: if the number of nonconforming items in the first sample is equal to zero, the lot is accepted but if the number of nonconforming items is equal to one, then second sample is taken and the policy of zero acceptance number would be appl...

in acceptance-sampling plans, the items of an incoming lot are inspected one by one. if the number of nonconforming items in sample is equal zero, the lot is accepted but if the number of nonconforming items is equal to one, then second sample is taken and the policy of zero acceptance number would be applied for the second sample. in this paper, a mathematical model is developed to design sing...

The nature of input materials is changed as long as the product reaches the consumer in many types of manufacturing processes. In designing and improving multi-stage systems, the study of the steps separately may not lead to the greatest possible improvement in the whole system, therefore the study of inputs and outputs of each stage can be effective in improving the output quality characterist...

| In this paper, we present new statistical sampling techniques for performing power estimation at the circuit level. These techniques rst transform the power estimation problem to a survey sampling problem, then apply stratiied random sampling to improve the eeciency of sampling. The stratiication is based on a low-cost predic-tor, such as zero delay power estimates. We also propose a two-stag...