Utah's Height and Weight Measurement Project was conducted with elementary school students periodically from 2002 to 2008. The 2002 pilot project was performed to establish variability rates between schools and within schools. It allowed us to accurately determine both the sample size and the number of schools that were required to calculate a reliable statewide estimate based on a random sampl...

Methods Web-based survey, containing discrete choice experiments (DCEs) to elicit preferences of three pre-defined groups of adults with epilepsy (n=750): (i) early epilepsy, (ii) established epilepsy, (iii) women of childbearing age (WOCBA). The DCEs contains five attributes, with two levels, defined using: semi-structured interviews with patients (n=56), a focus group with AED prescribers (n=...

PURPOSE Describe patient satisfaction and patient-reported outcomes after voluntary use of a telephone-based nurse triage service. METHODS A random sample of symptomatic callers who contacted the triage service in 1999 was identified. A computer-assisted telephone survey was conducted, resulting in a response rate of 58.9 percent and a sample size of 35,374. SUMMARY Overall satisfaction wit...

Inverse sampling design is generally considered to be appropriate technique when the population is divided into two subpopulations, one of which contains only few units. In this paper, we derive the Horvitz-Thompson estimator for the population mean under inverse sampling designs, where subpopulation sizes are known. We then introduce an alternative unbiased estimator, corresponding to post-st...

optimum sample size is an essential component of any research. the main purpose of the sample size calculation is to determine the enough number of units needed to detect the unknown clinical parameters or the treatment effects or the association after data gathering. it is not uncommon for studies to be underpowered and failing to detect the existed treatment effects due to inadequate sample s...

In chronic pulmonary diseases, the development of emphysema progresses over many years. As a result, the assessment of drug efficacy requires the observation of large numbers of patients, followed for long periods of time. Recently, lung densitometry has been studied as a potential clinical endpoint for the assessment of lung tissue loss over time in patients with emphysema. Clinical trials usi...

Sample size calculations are a critical step in the planning of any experiment. In all but the simplest of experimental designs, closed-form equations are not readily available, and statisticians are required to use simulations to estimate an appropriate sample size for the experiment. Specifically, when multiple explanatory variables are thought to be predictive of the response or when missing...

A probabilistic framework can be employed to assess the n“skof disclosure of confidential information in statistical databases that use disclosure control mechanisms. We illustrate how the method may be used to assess the strengths and weaknesses of two tm”stingdisclosure control mechanisms quey set size res&”ctioncontrol and random sample query control mechanisms. Our results indicate that nei...