Naslov
Use of Power Analysis in Choosing Appropriate Sample Size for Quality Inspection

Autori
Dumičić, Ksenija ; Žmuk, Berislav

Izvornik
Poslovna izvrsnost (1846-3355) 7 (2013), 1; 147-160

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, stručni rad, stručni

Ključne riječi
statistical power analysis ; sample size ; effect size ; Type I error ; quality inspection ; independent samples

Sažetak
Selection of an appropriate sample size is one of the most important aspects of any quality inspection. The right sample size enables making valid conclusions about the quality of the product with minimum necessary resources. The choice of sample size and the probability of Type II error (ß) are closely connected. The purpose of this paper is to examine how usage of statistical power analysis can improve researcher’s decision about choosing an appropriate sample size for experimental purposes and quality inspection. Besides sample size, the power of a study (1- ß) or the probability that the study yield significant results is determined by the magnitude of the treatment effect and by level of statistical significance required (α). Goal of power analysis is to balance values of these three factors to get an appropriate power. Impact of individual changes of each factor on the power was observed through a hypothetical statistical example based on significance test in which the difference between proportions of two independent samples was estimated. Power and Precision software is used for calculations. Results of power analysis have shown that increase of effect size, sample size and/or level of statistical significance leads to increase of power. That means if power increase and/or effect size and/or level of statistical significance would decrease, a larger sample size would be required. This paper demonstrates usefulness of using statistical power analysis in determining appropriate sample size and warns on possible consequences of erroneously selected sample size.

Izvorni jezik
Engleski

Znanstvena područja
Ekonomija

POVEZANOST RADA