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POSTGRADUATE METHODOLOGY COURSE. DESIGN AND ANALYSIS OF EXPERIMENTS: Basics. Hairul Hafiz Mahsol Institute for Tropical Biology & Conservation School of Science & Technology. Introduction to Design. What is Research Design?
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POSTGRADUATE METHODOLOGY COURSE DESIGN AND ANALYSIS OF EXPERIMENTS: Basics Hairul Hafiz Mahsol Institute for Tropical Biology & Conservation School of Science & Technology
Introduction to Design • What is Research Design? • Research design can be thought of as the structure of research -- it is the "glue" that holds all of the elements in a research project together. • We often describe a design using a concise notation that enables us to summarize a complex design structure efficiently.
The `blueprint’ for collecting, measure and data analysis. • It also help to allocate the limited source such as: • Choosing between the type of design • Experiment • Observation • Interview • Simulation • Collecting data whether in the form of structural or not. • Small or large sample • Quantitative or qualitative research
The research plan and structure regarding to answer the research question • Overall scheme or program starting from hypothesis writing, the operational implication to data analysis. • The design will showed the relation between variable and research plan to collect empirical data that related to the facing problems
Three questions: • What type of technique to be used for collecting data? • What type of sampling that will be used for the experiment? • How to save money and time consuming?
“figures never lie, only statisticians do” IS NOT TO BE REVIVED
POSTGRADUATE METHODOLOGY COURSE TYPES OF DESIGN STRUCTURES Completely Randomized Designs (CRD)
INTRODUCTION • If all the experiment material are homogenous or equivalent, the design structure that suitable to this situation is CRD. • The CRD is the simplest of all designs. • It is equivalent to a t-test when only two treatments are examined.
Field marks: • Replications of treatments are assigned completely at random to independent experimental subjects. • Adjacent subjects could potentially have the same treatment.
Sample layout: • Different colors represent different treatments. • There are 4 (A-D) treatments with 4 replications (1-4) each. • A: A1 A2 A3 A4 • B: B1 B2 B3 B4 • C: C1 C2 C3 C4 • D: D1 D2 D3 D4
A1 B1 C1 A2 D1 A3 D2 C2 B2 D3 C3 B3 C4 A4 B4 D4
The advantage • Easy to use • The experiment material can be used as many as possible • The treatment also can be used as many as possible
POSTGRADUATE METHODOLOGY COURSE TYPES OF DESIGN STRUCTURES The Randomized Complete Block design (RCBD)
INTRODUCTION • The RCB is the standard design for agricultural experiments. • The field or orchard is divided into units to account for any variation in the field. • Treatments are then assigned at random to the subjects in the blocks -once in each block.
Field marks: • Treatments are assigned at random within blocks of adjacent subjects, each treatment once per block. • The number of blocks is the number of replications. • Any treatment can be adjacent to any other treatment, but not to the same treatment within the block. • Used to control variation in an experiment by accounting for spatial effects.
Sample layout: • Different colors represent different treatments; each horizontal row represents a block. • There are 4 blocks (I-IV) and 4 treatments (A-D) in this example. • I: A B C D • II: A B C D • III: A B C D • IV: A B C D
Block I A B C D Block II D A B C Block III B D C A Block IV C A B D
The advantage • Block is used to be one of the error variation • Effect for the treatment will be higher.
POSTGRADUATE METHODOLOGY COURSE TYPES OF DESIGN STRUCTURES Latin Square Designs
The Latin Square design • The Latin square design is used where the researcher desires to control the variation in an experiment that is related to rows and columns in the field.
Field marks: • Treatments are assigned at random within rows and columns, with each treatment once per row and once per column. • There are equal numbers of rows, columns, and treatments. • Useful where the experimenter desires to control variation in two different directions
Sample layout: • Different colors represent different treatments. • There are 4 treatments (A-D) assigned to 4 rows (I-IV) and 4 columns (1-4).