1-4 Experimental Design

Question 1

observational study

Answer 1

the researcher merely observes what is happening or what has happened in the past and tries to draw conclusions based on these observations.

Question 2

three main types of observational studies

Answer 2

cross-sectional study, retrospective study, and longitudinal study

Question 3

cross-sectional study

Answer 3

data collected at one time

Question 4

retrospective study

Answer 4

data collected using records obtained from the past

Question 5

longitudinal study

Answer 5

data collected over a period of time, past and present.

Question 6

advantages of observational study

Answer 6

—- occurs in natural setting

Example: researchers can observe
people’s driving patterns on streets and
highways in large cities.

—— can be done in situations where it would be unethical and dangerous

—— cannot be manipulated

Question 7

disadvantages of observational study

Answer 7

—— cause-and-effect situation cannot be
shown since other factors may have had
an effect on the results.

—- can be expensive and time-
consuming.

—- There is no way to ensure the accuracy
of these records.

Question 8

Experimental study

Answer 8

the researcher manipulates one of
the variables and tries to
determine how the
manipulation influences other
variables,

Question 9

statistical experiment

Answer 9

researchers
intervened in the study by manipulating
one of the variables, namely, the type
of instructions given to each group.

Question 10

quasi-experimental study

Answer 10

when random assignment is not possible, researchers use intact groups - existing classroom

(experimental study should be random)

Question 11

independent variable ( explanatory variable)

Answer 11

the one that is being manipulated

by the researcher.

Question 12

Dependent variable ( outcome variable)

Answer 12

resultant variable, used to see if it changed significantly because of the manipulation of the independent variable

Question 13

treatment group

Answer 13

group that receives special instructions

Question 14

control group

Answer 14

group that does not receive special instructions

Question 15

advantages of experimental study

Answer 15

— researchers can decide how to select subjects and how to assign them to specific groups

—-

Question 16

Disadvantages of Experimental study

Answer 16

—- occur in unnatural setting

— Hawthorne effect

Question 17

Hawthorne effect

Answer 17

subjects know that they are participating in an experiment and changed behavior in ways that affected the results

Question 18

confounding of variables or lurking variables

Answer 18

influences the dependent
or outcome variable but was not
separated from the
independent variable.

Question 19

placebo effect

Answer 19

subjects used in
the study respond favorably or show
improvement due to the fact that they
had been selected for the study.

Question 20

blinding

Answer 20

minimize placebo effect, subjects do not know if they are receiving treatment or a placebo

Question 21

double blinding

Answer 21

subjects and researchers are not told which groups are given the placebo

Question 22

blocking

Answer 22

minimize variability

Question 23

completely randomized design

Answer 23

subjects are assigned to groups randomly

,and treatment are assigned randomly

Question 24

matched-pair design

Answer 24

one subject is
assigned to a treatment group, and
another subject is assigned to a control
group. But, before the assignment,
subjects are paired according to certain
characteristics (age, height, weights)

Question 25

replication

Answer 25

Here the same
experiment is done in another part of
the country or in another laboratory and the second study is compared to the original

Question 26

lurking variable

Answer 26

a variable that influences the relationship between x and y, but was not considered in the study