Types of Probability Sampling Techniques:
1.The sampling interval 
tells the researcher how to select elements from a sampling frame by skipping 
elements in the frame before selecting one for the sample.Systematic Sampling
 Elements are randomly selected using a sampling interval.One way of 
obtaining a random sample is to give each individual in a population a number, and 
then use a table of random numbers to decide which individuals to include
A specific advantage is that it is the most straightforward method of probability 
sampling.A disadvantage of simple random sampling is that you may not select enough 
individuals with your characteristic of interest, especially if that characteristic is 
uncommon.?2.