Sampling is defined as a process that is used in statistical analysis in which a predetermined number of observations will be taken from larger population.
In the question given we will be looking at two types of sampling:
- Purposive Sampling
- Descriptive Sampling
1. Purposive Sampling
Also known as judgmental sampling, purposive sampling is a form of non-probability sampling technique. It is defined as the sampling used in a cases where there us a specialty of authority that can be used as a means of a representative sample in order to bring more accurate results that using probability sampling techniques. Basically, the process requires handpicking individuals from the population based on the individuals knowledge, authority or judgement, and this forms the sample representation for the entire population.
Example: A research wants to determine how to obtain a perfect score for one's SATs, and the only individuals that can answer this question is students who excel at their SATs.
2. Descriptive Sampling
Descriptive sampling (also called descriptive statistics) is defined as a sample of data that enables the analyzing of data that helps describe, show or summarize data in a meaningful way.
Example: The class average for mathematics for grade 10 was 60%. This only tells us the mean of the class. We know that not everyone scored 60%, some scores will be very high and some very low. Now descriptive sampling allows us to determine how widespread the data with the use of standard deviation, range, inter quartile range and variance.