There are a multitude of available test procedures and methods for water and wastewater treatment operators. They range from colorimetric, titrimetric, electrometric (meter & probe), turbimetric, ...

Hardness testing may not be a fundamental physical property, but that does not mean it is not an important property to test and measure. This article discusses methods and the principles behind ...

This paper presents a method for assessing bias in test items. In this procedure an unbiased item is defined as an item for which the probability of a correct response is the same for any person of a ...