Difference between examples

Difference between first example and second example

First example:
· In this example, researcher decides to carry out a survey.
· In this example, the sample is selected randomly that is out of 1000 primary school
teachers in Mumbai 300 are randomly selected.
· In this there is only one group that is 300 randomly selected samples on basis of which her
survey will be done.

Second example:
· In this example, researcher decides to carry out a study that is the actual experiment is
carried out by giving treatment to the group.
· In this example, the selection of sample is random but with different method the
sample is selected that is researcher 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.
· In this, there are two groups since there are two different CAI packages of which
effectiveness has to be checked