Research Design New

RESEARCH DESIGN Research design is the arrangement of conditions for collection and analysis of data in a manner that aims to combine relevance to the research purpose with economy in procedure. (OR) Research design constitutes the blue print for the collection, measurement and analysis of data. It aids the scientist in the allocation of his limited resources by posing crucial choices.

RESEARCH DESIGN • NEED FOR A RESEARCH DESIGN – It facilitates the smooth sailing of the various research operations – It yields maximum information with minimum expenditure of effort, time and money – To organize ideas and how to overcome the flaws and inadequacies in the process.

The Nature of Good Design • Theory-Grounded. Good research strategies reflect the theories which are being investigated. Where specific theoretical expectations can be hypothesized these are incorporated into the design.

RESEARCH DESIGN Important Concepts Relating to Research Design

• The group in an experiment which receives the specified treatment is called the Treatment Group or the experimental group. However, the term Control Group refers to another group assigned to the experiment, but not for the purpose of being exposed to the treatment. Thus, the performance of the control group usually serves as a baseline against which to measure the effect of the full treatment on the treatment group.

Important Concepts Relating to Research Design • Variance refers to the variability of any event. If one uses a fine enough measuring device, one can find differences between any two objects or events. • Blocks usually refers to categories of subjects with a treatment group. For example, we might divide the group into older, middle aged, and younger patients and further divide the groups into a group treated with Drug A and another treated with Drug B. The advantage is to enable us to discover how the treatment affects each of the age groups. For example, we might find that overall, Drug B out performs Drug A, except for older patients, where Drug A out performs Drug B. This phenomenon is known as an interaction between treatment (the Drug) and subject characteristics (age).

Important Concepts Relating to Research Design • Dependent and Independent Variable : – If one variable depends upon or is a consequence of the other variable is termed as an dependent variable. – The variable that is antecedent to the dependent variable is termed as an independent variable. – Extraneous Variable : Independent variables that are not related to the purpose of the study, but may affect the dependent variable are termed as extraneous variables.

Important Concepts Relating to Research Design • Confounded relationship: When the dependent variable is not free from the influence of extraneous variable(s), the relationship between the dependent variable and independent variables is said to be confounded by an extraneous variable(s).

Important Concepts Relating to Research Design

• Research Hypothesis: When a prediction or a hypothesized relationship is to be tested by scientific methods • Experimental hypothesis-testing research: When the purpose of research is to test a research hypothesis is termed as experimental hypothesis-testing research. • Non-Experimental hypothesis-testing research: A research in which an independent variables are not manipulated.

Important Concepts Relating to Research Design • Experimental and Control Group: In an experimental hypothesis-testing research when a group is exposed to usual conditions, it is termed a ‘control group’, but when the group is exposed to some novel or special treatment, it is termed as ‘experimental group’.

Important Concepts Relating to Research Design • Treatments: The different conditions under which experimental and control groups are put are usually referred to as “ treatments”. • Experiment: The process of examining the truth of a statistical hypothesis, relating to some research problem, is known as an experiment. • Experimental Units: The pre-determined plots or the blocks, where different treatments are used, are known as experimental units.

Types of Research Design Research Design

Exploratory/ Formulative

Descriptive/ Diagnostic

Overall Design

Flexible Design( design must provide an opportunity for considering different aspects of the problem

Rigid Design ( Design must make enough provision for protection against bias and maximum reliability)

Types of Research Design Sampling Design

Statistical Design

Nonprobability sampling design ( purposive or judgment sampling No pre-planned design for analysis

Probability sampling design ( random sampling)

Pre-planned design for analysis

Types of Research Design Observational Design

Unstructural instruments for collection of data

Structured or well thoughtout instruments for collection of data

Operational Design

No fixed decisions about operational procedures

Advance decisions about operational procedures

CHAPTER-4

EXPERIMENTAL RESEARCH DESIGNS

EXPERIMENTAL RESEARCH DESIGNS

Experimental Designs refers to the framework or structure of an experiment.

Experimental Design Experimental Design refers to the framework or structure of an experiment Informal Experimental Formal Experimental Design Design Before & After without control design

Complete Randomized Design

After-only with control Randomized Block Design design Before & After with control Latin Square Design design

Informal Experimental Design • Before and After without control Design: In such a design a single test group or area is selected and the dependent variable is measured before the introduction of the treatment. The treatment is then introduced & the D.V is measured again after the treatment has been introduced. Test area: Level of phenomenon Treatment Level of Phenomenon Before treatment( X ) introduced after treatment( Y) Treatment Effect = (Y)-(X)

Before-and-after without control design • Main difficulty-passage of time considerable extraneous variations may be there in treatment effect

Informal Experimental Design • After only with control Design :

In this design two groups or areas are selected and the treatment is introduced into the test area only. The D.V. Is then measured in both the areas at the same time Test area: Treatment introduced Level of Phenomenon after treatment( Y) Control Area Level of phenomenon Without treatment (Z) Treatment Effect = (Y)-(Z)

After only with control design • Assumption-two areas are identical with respect to their behaviour

Informal Experimental Design • Before and After with Control Design: In this design two areas are selected and the D.V. is measured in both the areas for an identical time-period before the treatment. The treatment is then introduced into the test area only, and the D.V. is measured in both for an identical time period after the introduction of the treatment.

Before and After with Control Design: Time Period I Time Period II Test Area: Level of Phenomenon Level of phenomenon before treatment ( X) after treatment( Y) Treatment introduced Control Area: Level of Phenomenon without treatment( A)

Level of phenomenon without treatment ( Z)

Treatment Effect = ( Y-X) - (Z-A)

BEFORE AND AFTER WITH CONTROL DESIGN • Superior-it avoids extraneous variation • Non comparibility of test and control areas • At times due to lack of historical data,time and comparable control area

Formal Experimental Design Complete Randomized Design ( C.R.Design) Involves only two principle – The principle of replication – The principle of Randomization – Subjects are randomly assigned to experimental treatments – When all the variations are due to uncontrolled extraneous factors are included under the heading of chance variation, we refer to the design of experiment as C.R.Design.

Complete Randomized Design ( C.R.Design) • Two Group Simple randomized design:

population

Randomly selected sample

experimental

T;A

Randomly assigned

I.V control

T:B

Complete Randomized Design ( C.R.Design) • Random Replication Design: It serves two purposes • It provides controls for the differential effects of extraneous independent variables • It randomizes any individual differences among those conducting the treatments

Formal Experimental Design • Randomized Block Design ( R.B.Design)

– All the three principles are taken care off – In this the subjects are divided into groups, known as blocks, such that within each group the subjects are relatively homogenous in respect to some selected variable. – Each treatment appears the same number of times in each block – R.B.Designs are analyzed by the two way analysis of variance ( two way ANOVA) technique.

Randomized Block Design ( R.B.Design) V.Low I.Q

Low I.Q

Average I.Q

Student Student Student

High I.Q

V.High I.Q

Student Student

Form1

82

67

57

71

73

Form2

90

68

54

70

81

Form3 Form4

69 86

73

51

93

77

60

65

84 71

Formal Experimental Design • Latin Square Design ( L.S.Design) – Very frequently used in agricultural research. – Used when there are two major extraneous factors – The treatment in L.S. are so allocated among the plots that no treatment occurs more than once in any row or column – Five types of fertilizer ABCDE $Two blocking factors(varying soil fertility$varying seeds) may be represented through rows and columns. – Two way ANOVA technique is used. – 5x5 to 9x9

Latin Square Design ( L.S.Design) I

II

III

IV

V

X1

A

B

C

D

E

X2

B

C

D

E

A

X3

C

D

E

A

B

X4

D

E

A

B

C

X5

E

A

B

C

D

Factors affecting Research Designs • • • • • •

Non availability of the sufficient data Availability of Time Availability of resources Ability of the Researcher External Factors Result Desired

VALIDITY • By validity, we mean simply that the researcher’s conclusion is true or correctthat it corresponds to the actual state in the world. Validity is an indicator of accuracy in terms of the extent to which a research conclusion corresponds to reality.