Mean difference in the weight of a product by t student test hypothesis and confidence interval

Abstract

Hypothesis testing (PH) and confidence interval (CI) are very useful statistical procedures to infer about unknown values of a population, for example when the variance (02) is unknown. This paper presents the application of these methods of estimation to see if there is a difference in the average of the variable weight of a product of two different shifts (A and B), and decide whether the process presents significant changes in the total population of products. The mean difference test is a widely used in statistical quality control and provides substantial information processes in technical areas of production; to perform this statistical test samples in the corresponding shifts were taken and an equation for samples containing less than 30 elements, which come from normal populations and unknown variances was applied; the test showed no difference between the means of the population in the weight of the product to give values of the test statistic (t) less than t tables to a level a=5% with 12 degrees of freedom.