HP provides a type of model name near the keyboard or screen, but this name or number is probably not sufficient to get proper support for your computer. These names or numbers often represent a series of many notebook computers that look similar, but have different options and parts.
Fundamentally, river sampling is a web-based convenience sample of opt-in participants that uses a quota sampling approach to build a study sample. The selection method is not probability based, and participants cannot be described as representing any larger defined population.
Systematic sampling is quick and easy to do. But it is easy to miss variation. For example, if you are investigating downstream changes in a river by choosing equally spaced samples, you may not easily be able to pick out the effect of tributaries joining the river.