Systematic sampling is a commonly used technique due to its simplicity and ease of implementation. The drawback of this simplicity is that it is not possible to estimate the design variance without bias. There are several ways to circumvent this problem. One method is to suppose that the variable of interest has a random order in the population, so the sample variance of simple random sampling ...

Sampling is a fundamental operation for the auditing and statistical analysis of large databases. It is not well supported in existing relational database management systems. We discuss how to obtain samples from the results of relational queries without first performing the query. Specifically, we examine simple random sampling from selections, projections, joins, unions, and intersections. We...

This study proposes ratio estimators by adapting the estimators type ofRay and Singh [J. Ind. Stat. Assoc. 19 (1981) 147] to traditional and the other ratio-type estimators in simple random sampling in literature. Theoretically, mean square error (MSE) equations of all proposed ratio estimators are obtained and compared with each other. By these comparisons the conditions, which make each propo...

We present a simple algorithm for estimating the cardinality of a set I, based on a RandomSample(I) primitive that returns an element of I uniformly at random. Our algorithm with probability (1−perr) returns an estimate of |I| accurate within a factor (1 ± δerr) invoking RandomSample(I) at most O (