the dfference in examples!

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.
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.

In the first example, it is definitely a random selection. and in the other example, though the selection of the target population is through convinience, but the sample she has selected in a random manner.

difference between the 2 sampling

The major difference according to me between simple random sampling and convenience sampling is
1.
That each individual is chosen entirely by chance and every individual has the same chance of getting selected. I.e. it represents the entire population.
And convenience sampling is based on easy availability of the sample. Therefore, Convenience sampling does not represent the entire population so it is considered bias.
2.
There is a systematic way of choosing the sample
Whereas, in the case of convenience sample, one can randomly choose a location and make them their sample.

heyyy !!! another blog huh??!! this is so cool.. i think i m going to make use of this even personally.. hehe i hope i dont get bored of it.. u knw.. since i hv a tendency to get bored of anything n everything in life.. neways.. have to go for now, see you around!!!