Pros And Cons Of Reseaech Designs And Sampling

Question 1

PROS OF REPEATED MEASURES

Answer 1

Using the same participants as the E-group and the C-group means
that confounds caused by ‘participant variables’ will be eliminated. It is also
possible to use fewer participants than with other designs.

Question 2

CONS OF REPEATED MEASURES

Answer 2

The repeated measures procedure takes a long time – participants
have to take part in both conditions, so ‘drop-outs’ are likely. The procedure can
also suffer from confounding variables known as order effects:
– Participants may perform better on the task when doing it a second time
because of the effect of practice.
– Participants may do worse the second time because of fatigue or boredom.

Question 3

COUNTERBALANCING

Answer 3

. In the
counterbalancing procedure, half the participants will first perform the task with the
IV present (experimental condition) and then perform the task with the IV absent
(control condition). The other half of the participants will experience the conditions
in the reverse order. Random selection should be used to decide which participants
perform the tasks in which order.

Question 4

MATCHED PARTICIPANTS

Answer 4

In the matched participants design a researcher identifies a variable that is a likely
confound, and eliminates the effects of this variable from the experiment. Participants
can be ranked in accordance with their scores on this variable and then allocated to
the respective groups.

Question 5

PRO OF MATCHED PARTICIPANTS

Answer 5

Advantage: The variable on which the participants are ‘matched’ will not influence
the results because its effects will be the same in the E-group and the C-group.

Question 6

CON OF MATCHED PARTICIPANTS

Answer 6

It is very time-consuming (and therefore expensive) to find out the
value of this variable for each participant. Also, if one of the pair drops out, the
scores for the other must also be eliminated.

Question 7

PRO AND CON OF INDEPENDENT GROUPS

Answer 7

Advantage: The independent groups procedure can all be done at once and dropouts
are unlikely.
» Disadvantage: The procedure needs a large number of participants to ensure that
the spread of participant variables in the sample will match the spread in the
population.

Question 8

PRO AND CON OF RANDOM SAMPLE

Answer 8

Gives representative sample -
participant variables spread in same
proportion as in population

Difficult to achieve - the larger the
population, the harder it is to list
all individuals

Question 9

PRO ANF CON OF STRATIFIED

Answer 9

Eliminates the effect of the variable on
which the sample is stratified

Time-consuming; expensive

Question 10

STRATIFIED

Answer 10

Dividing population into categories
and selecting at random in proportions
equivalent to population

Question 11

PRO AND CON OF CONVENIENCE

Answer 11

Quick, easy, cheap - this is the
most common method of sampling

Bias in sample

Question 12

OPERATIONALISE

Answer 12

STATED IN TERMS OF HOW ITS MEASURED