Microbiology 9th Edition by Laura Black, Jacquelyn Black

تمرين 9

An epidemiological study in which an investigator tests the hypothesis that a particular treatment will be effective incontrolling a disease for which no accepted cure is available is known as a(n) study.
(a) Descriptive
(b) Analytical
(c) Experimental
(d) Prospective
(e) Retrospective