part of the research design

1. M.A. 1ST SEM
D.A.V. PG COLLEGE, VARANASI

2. A randomized group design is one in which subjects are
randomly assigned to the different groups meant for
the different conditions or values of the independent
variables
The random assignment of subjects into two or
more groups will make these groups statistically
equivalent on the subject relevant variable which
may produce variations in the dependent variable

3.  In this design subjects are randomly assigned to two groups only. Experimenter, first define independent
variable and then dependent variable.
 Experimenter selects two values of the independent variables. These two values may also be called as
“CONDITIONS” or “TREATMENT” of the experiment.
NO TREATMENT PROVIDE

4.  It is expected that these two randomly assigned groups will not differ significantly at the start of
experiment.
 It is not necessary that in a randomized group design the numbers of subjects in each group
should be equal. But the equal N is preferred because it facilitates some statistical calculations
(Edward, 1968; Winer, 1971)
UNDERWOOD(1966) has suggested two primary ways through which random groups
of subject can be formed:
In this technique, all subjects are individually know to
the experimenter by name and they all present at one
time. In a way there are made captive for the entire
duration of the experiment so that they can at
random be assigned to the different conditions or
groups .

5.  In this technique , experimenter does not
know the details of the subjects. He is
simply aware of the fact that a certain
numbers of subjects will participate in the
experiment.
 As the experiment in the randomized
group design usually continues for several
days or week. The experimenter may use
5 subjects on 1st day, 2 subjects on 2nd day,
6 subjects on 3rd day and so on. Thus the
experiment is conducted in a prearranged
sequence.
 If the subjects are not representative of the original randomly assigned
groups, it is obvious that these equivalent groups resulting from
random assignment may no longer be really equivalent and then
conclusions drawn may not be generalized.
 In this design only two values take part in experimentation, it is
difficult to state precisely the exact relationship between influential
independent variable and dependent variable.

6. In such a design there are three or more conditions or values of the independent
variable and accordingly, three or more groups of subject participate in the experiment.
The design is so called because the total subjects are randomly assigned to three or more
unbiased groups.
The process of captive assignment as well as the process of sequential assignment may
be utilized as the techniques of random assignment of subjects into three or more
groups.
In psychological researches the use of more-than-two randomized group design is more
common than the two – randomized group design.
 In multi – groups design the two most common statistics applied are the “analysis of
variance” and the “Duncan Range Test”.