IS randomness only of ONE type??

Hello girls!
I’m sorry for the delay that has gone into putting up the posts so far.
Anyway, moving on, in the post named “Random and non-random, that’s it” we saw the 2 broad categories of sampling ‘random/probability sampling’ and ‘non-random/non-probability sampling’.
As opposed to random samples, non-random samples never aim at achieving generalisability or randomness. There are different ways, in which this randomness is achieved. For this, let us take a look at the following examples:

1. A researcher wants to find out the opinion of primary school teachers on the increasing amounts of size and weight of children’s’ schoolbags. She decides to carry out a survey for this purpose. Out of the 1000 primary school teachers in Mumbai, she decides to select 300 teachers randomly for her study.
2. A teacher at a university wants to find out whether there is any difference caused in the academic achievements of students after using 2 different kinds of CAI packages - one with linear interactivity and the other with non-linear interactivity. She decides to carry out the study on her own batch of 50 students. Since there are 2 kinds of CAI packages to be implemented, she makes 2 groups in the following way:
   She lists everyone’s names on chits, and draws one chit out of the lot and writes that name under a column named linear CAI and puts that chit aside. Then she picks another one, this time writing the name under a column named non-linear CAI. She proceeds in this way until all chits have been randomly distributed under the 2 columns and she is ready with 2 groups of students for her study.

By looking at these 2 examples, do you see any difference in the way the participants of the study were selected?
I suggest you write the differences you see in the 2 examples on your own blog. You may copy - paste the examples in your post for your reference.
As usual my post will follow all your posts…See you till then..!