Experimental Studies

Question 1

Experimental studies are scientific investigations in which the investigator influence / manipulates the study procedure by ___________ or __________ the study groups of a defined factor and consequently studying the effects of the ____________(___________) or the _____________(_________) of a defined factor.

Answer 1

exposing or depriving

exposure (addition)

deprivation (denial)

Question 2

There are two major types of experimental studies.

They are ________ or ________ Experimental studies (______________________ Trials) and
_________ Experimental studies

Answer 2

True or Classical

Randomised Control

Quasi

Question 3

Study setting
Based on this classification, there are three types of Experimental studies.

___________ trials
___________ trials
___________ trials

Answer 3

Clinical trials
Field trials
Community trials

Question 4

__________ is a technique to eliminate bias in experimental studies.

Answer 4

Blinding

Question 5

Blinding refers to the situation in which __________________________________ are unaware of who is being exposed or deprived of the factor under investigation.

Answer 5

either the investigator or the subject or both

Question 6

Blinding

Single blinding or single blind experiment is when _____________________ is unaware of who is exposed or deprived of the factor under investigation
Double blind experiment is one in which __________________ are unaware of who is exposed or deprived of the factor under study
Triple blinding, _________________________ are all unaware of who is exposed or deprived of the factor under study

Answer 6

either the investigator or the subject

both the investigator and the subject

the investigator, the subject and the evaluator

Question 7

Quasi-experimental study designs
A quasi-experimental study is a study design in which _______________________
It may be characterized by the presence of a manipulation/ intervention and the absence of either randomization or control in the study design.

Answer 7

one or more of the requirements for an experimental design is lacking.

Question 8

One of the largest field trials was that testing the __________ for the prevention of ____________, which involved over one million children.

Answer 8

Salk vaccine

poliomyelitis

Question 9

Bias is any ________________r in the determination of the association between the exposure and disease.

Answer 9

systematic erro

Question 10

2 Examples of bias

Answer 10

Selection bias
Measurement (or classification) bias

Question 11

Validity is an expression of the degree to which a test is capable of _________________.

A study is valid if _______________________ ; there should be no systematic error (bias) and the random error should be as small as possible.

Answer 11

measuring what it is intended to measure

Question 12

Experimental studies are particularly suitable for testing and establishing ________________ and the ____________________ because their design eliminates potential alternative explanations.

Answer 12

cause-effect relationship

effectiveness of interventions

Question 13

Field trials

●Field trials, in contrast to clinical trials, involve people who are ________ but ________________
• Data collection takes place “————— ,” usually among non-institutionalized people in the general population.

Answer 13

healthy; presumed to be at risk

in the field

Question 14

Field Trials

• Since the subjects are __________ and the purpose is to ____________ that may occur with relatively (low or high ?) frequency, field trials are often logistically ____________ and an _________ endeavours

Answer 14

Disease free

prevent diseases; low

complicated; expensive

Question 15

Internal validity VS external validity

Answer 15

Internal validity is the degree to which the results of an observation are correct for the particular group of people being studied.

External validity or generalizability is the extent to which the results of a study apply to people not in it.