Which types of sampling method is ideally suited, where there is no knowledge about population?

The French social philosopher who gave stress on scientific theories and observation was

A. H. Maine

B. E. Durkheim

C. A. Comte

D. H. Spencer

By which of the following means objective facts cannot be secured or established by a researcher?

A. By observation and experiment

B. By research

C. By objective analysis of data

D. From material collected on the basis of oath and affirmation

Field study is a method of research in which the observations are taken in the

A. Natural set up

B. Observed set up

C. Laboratories

D. Fields

The validity and reliability of a research will be at stake when

A. The incident was reported after a long period of time from that of its occurrence

B. The author who is the source of information is biased, incompetent or dishonest

C. The researcher himself is not competent enough to draw logical conclusions

D. All of the above