Answer:
a
A sample survey; we want to gather information about a population based on a sample.
b
An experiment; we want to establish a cause-and-effect relationship
c
An observational study; there is no particular population from which we will sample, we simply observe.
Explanation:
Considering the first question
Are people generally satisfied with how things are going in the country right now?
Here the aim is to gather the opinion of the entire population and since it is impossible to ask each and everyone that make up the population then the best option is to taken a sample of the population and then draw conclusion from their opinion
So the correct option to question a is
A sample survey; we want to gather information about a population based on a sample
Considering the second question
Do college students learn basic accounting better in a classroom or using an online course?
Here in other to get the best answer to the question there is need to carry out a statistical experiment using a group of college student where by a particular group of college student is exposed to learning a particular topic through class room and another group of college student is exposed to learning the same subject through online and then the same test is given to both group of student to determine the outcome of the experiment.
So the solution to the question b is
An experiment; we want to establish a cause-and-effect relationship
Considering the third question
How long do your teachers wait on the average after they ask their class a question?
For the above question we see that in order to get the correct solution to this problem there is a need to observe the teachers during question and answer section of their teaching so the correct answer to this question is
An observational study; there is no particular population from which we will sample, we simply observe.