copy of v research design

8/7/2019 Copy of v Research Design

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V Research Design


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What is research design?

Blueprint for collection, measurement and

analysis of data.

It is the conceptual structurew

ithinw

hichresearch is conducted ; it comprises the planfor collection, measurement & analysis ofdata.

It is logical and systematic plan prepared fordirecting research study.


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Definition of research design

Research design is an aid for researcher in the

allocation of limited resources by posing

crucial choices in methodology.

It is procedural plan that is adopted by the

researcher to answer questions validly,

objectively, accurately and economically.


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What is Research Design

What is essential

Activity & time based plan

Based on research problem / objectives

Guide for selecting sources and type of information

Procedural outlines

Framework for specifying relationship amongst study

variable


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Components of research design

Sampling design

Deals with the method of selecting items to be observed for the givenstudy.

Observational Design

Relates to the condition under which observations are to be made.

Statistical Design Concerns with the questions of how many items are to be observed

(sample size) and

how information and data gathered are to be analysed

Operational Design Deals with implementation part.

How the techniques and procedures specified will carried out.


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Features of good design

Minimise bias and maximises the reliability of the

data collected and analysed.

Yields maximal information and provides an

opportunity for considering many different aspect of

the problem.

Design is related with purpose and objective of the

study.

Flexible, appropriate, efficient, economical.


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Types of research Design

Research Design for exploratory research

Research Design for Conclusion oriented research Research Design for Descriptive research

Cross sectional

Longitudinal

Research Design for Causal research Pre experiment

True Experiment

Quasi Experiment

Complex designs Simple factorial

Complex factorial


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Exploratory Vs Descriptive research Designs

Exploratory /

Formulative

Descriptive /

Diagnostic

Overall

Design

Flexible (opportunity to

explore the different aspectsof problem)

Rigid (maximize reliability of

the outcome and reducesbias)

Sampling

Design

Non probability Probability

Statistical

Design

No preplanned Design for

analysis

Pre planned design for

analysis

Observation

al Design

Unstructured Instruments

used for data collection

Structured and well thought

and designed instruments for

data collection

Operational

Design

No fixed decision regarding

operational procedures

Advanced decision regarding

operational procedures


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Experimental Method


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What is experimentation?

Studies involving

intervention (to manipulate some variable)by researcher


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Advantages

Manipulation

Control

Convenience

Cost

Replication


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Disadvantage

Setting up the laboratory

Chances of cost overruns

Past things can not be studied

Ethicality (as social research is related with

people extent to which one can

manipulate??)


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Experimental Designs

Examines differences betweenexperimentally manipulated groups orvariables (e.g., one group gets a certain drugand the other gets a placebo).

At minimum, experimental (independent)variable has two levels (e.g., drug vs.placebo).

Advantage is that you can determine causality. Disadvantage is cost and many variables cannot

be experimentally manipulated (e.g., smokeexposure over time).


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Four Canons for Identifying Causality

Method of Agreement

Observe the element common to several

instances of the event Problem is you may inadvertently overlook a

significant variable.

Method of Difference

Identify the different effects produced by twosituations that are alike in all ways but one.

Fairly robust and strong method.


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Four Canons for Identifying Causality

Joint methods of agreement and difference

Observe the element common to several instances of theevent

Form hypothesis based on observations

Test hypothesis using method of difference

Method ofConcomitant Variation

Identify the different effects produced by more than twosituations that are alike in all ways but one.

E.g., Compare two active drugs to a placebo


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Experimental Design

Because it is so difficult with human behavior

to demonstrate causation unequivocally, some

argue that a theory or prediction can onlyachieve the status of not yet disconfirmed

(Popper, 1968).

Our scientific efforts are directed at finding thecausal factors rather than the cause per se.


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Psychological Experiment:

Is Objective

Researcher strives for freedom from bias.

Recognize that:

Mistakes can occur

Carefully scrutinize all steps of the experiment to

identifywhere mistakes are likely.

Take the steps necessary to minimize error.


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Focuses on a Phenomenon

This is a publicly observable behaviour.

Actions

Appearances Verbal statements

Responses to questionnaires

Physiological responses.


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Is Done Under Strictly Controlled

Conditions

Eliminate all factors that could influence

the outcome other than the factor being

manipulated.

Control is needed to infer causation.

All conditions are kept constant except one;

the manipulated variable.

The variable of interest is varied in order to

test its effect.


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Experimental Method

Advantages

Strength with which causal relationships can be

inferred.

Ability to manipulate one or more variables.

Proven to be a very useful and robust scientific

method (i.e., withstood the test of time).


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Experimental Method

Disadvantages

Tight controls often produce artificial

conditions that could limit the generalizabilityof the findings (i.e., internal vs. external validity

trade-off).

Time consuming.

Expensive.

Human behavior is very complex and cannot be

fully studied using experimental methods.


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Experimental Method:

Threats to Internal Validity Learning or practice effects

Scores on a measure change on repeat testing becauseparticipant has more familiarity with the measure andso answers more truthfully.

Natural history effects Something happens in the social background (e.g.,

society because more affluent generally) and thisinfluences the participants responses.

Maturation Natural developments in the participant account for

the changes (e.g., getting older).


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Threats to Internal Validity

Regression to the mean

High scores generally move down toward the

mean and low scores move up.

Instrumentation

If pre and post tests are not equivalent in all

ways (e.g., difficulty, readability) then

differences observed may be due toinstrumentation differences rather than due

to your experimental manipulation.


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Threats to Internal Validity

Subject problems

Selection bias (e.g., participation rate).

Attrition (e.g., only motivated subjects stay in

the experiment).


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Threats to External Validity Subject variables

Selection bias.

Attrition bias

Artificial conditions E.g., In order to measure a subjects blood pressure in

response to a well-fined stressor you bring him/her

into the laboratory but his/her response in the

laboratory may not reflect how his/her blood pressure

would really respond under stress in his natural

environment.


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The independent variable is the variable that is

purposely changed. It is the manipulatedvariable.

The dependent variable changes in response to

the independent variable. It is the responding

variable.

Variables

Variables are things that change.


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Constants or Controlled Variables

in an ExperimentWhat are constants in an experiment?

Factors that are kept the same and not

allowed to change.

It is important to control all but onevariable at a time to be able to

interpret data


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Sample experiment with data

Studentswere asked to build a helicopter and

test something.


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Writing A Statement of the

Problem for the Experiment

It should state: The Effect of the Independent

Variable on the Dependent Variable.

A good statement of the problem for The

Helicopter would be

The Effect of wing length on time of decent

What should it state?


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More about our variables:

The independent variable is the variable that is

purposely changed. It is the manipulated variable.

The dependent variable changes in response to the

independent variable. It is the responding variable.

What is the Helicopter independent variable?

length of one wing as measured in centimeters

What is the dependent variable?

time of descent as measured in seconds


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Title for the Helicopter Experiment

The Effect of Wing Length on the Length

of Time the Helicopter Takes to Reach

the Ground


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Another Look

at Our Hypothesis

INDEPENDENT VARIABLE

If the length of the wings are increased,

DEPENDENT VARIABLE

then time of descent will increase.


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Constants in an ExperimentFactors that are kept the same and not

allowed to change

What should be kept constant in theHelicopter?

CONSTANTS

Same structure of helicopters

Same dropping technique

Same dropping height


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Values of the Independent Variable

How many different values of the

independent variable should we test?

Enough to clearly illustrate a trend in

the data - 5cm, 6cm, 7cm, 8cm..


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Repeated Trials

How many repeated trials are needed in the

Helicopter?

At least 3, then calculate an average value

for each level of the independent variable


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Drawing of Experiment

Hold helicopter

in the middle

Drop from

same spot

each time


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QualitativeObservations and Results

As we dropped the helicopter, we

observed that sometimes they

seemed to be affected by aircurrents.

It appeared that helicopters with

longer wingspans took a greater

time to reach the ground


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Quantitative Observations

Data Table, Graph and

Statistics


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Sample Data Table

Title: The Effect ofwing length on the time of descent

Wing Length

(cm)

Average Descent

Time (s)

Descent Time (s)

Trials

1 2 3

56

7

89

3 5 4 44 5 6 5

6 7 5 6

7 8 6 79 7 8 8


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The Effect f Wi Length n Descent Time

0

1

2

3

4

5

6

7

8

9

0 1 2 3 4 5 6 7 8 9 10

Average Wing Length (cm)

AverageDescen

tTime(s)


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Analysis and Interpretation of

ResultsWhile individual trial results showed some

variation; overall, as average wing length

increased from 5 through 9 centimeters,

average time of descent also increasedfrom 4 through 8 seconds.

This shows a direct correlation.


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Possible Experimental Errors

Although the average results supported the

hypothesis, the individual trial results showedsome variation. Some possible reasons for this

could be due to air currents in the room or

reaction time differences between the timer

and the helicopter dropper.


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Conclusion

The overall results supported the

hypothesis.

A possible reason for this could be

due to increased surface area of the

wing in contact with the air - allowing

for greater air support.


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Recommendations for Further Experimentation/

Practical Applications

Increased time of descent due to greater wing length

suggests that increased wing length could lead to

greater fuel efficiency of an actual helicopter.

Other experiments investigating factors that would

contribute to greater descent time might include:

making modifications in the shape of the wings,

changing the number of wing blades, and making foldsin the wing blades

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