Research technique

Marzuqi Salleh, UiTM Perlis

FINAL QUESTION AND ANSWER

(COLLECTION)

RESEARCH TECHNIQUE

RESEARCH TECHNIQUE CONFIDENTIAL


PREPARED BY: MARZUQI BIN MOHD SALLH

Give the definition or explain the meaning of the following terms:
a) Replication
• A treatment is repeated two or more times in a particular experiment
b) Competition
• Competition is greatest between individual plants of the same species because they
make similar demands on the habitat factors at the same time as well at the same level
c) Minimum plot size
• Size of plots in field experiments has much to do with the accuracy, value and
importance of results
d) Null hypothesis
• Claim (or statement) about a population parameter that assumed to be true until it is
declared false
e) Factorial experiment (10 marks)
• A study with two or more factors in combination.
• Not a design but an arrangement.

Give the definitions or explain the meaning of the following terms: (10 marks)
a) Completely Randomized Design (CRD)
• It is usually used in laboratory, growth chamber, or rain shelter experiments because of
the environmental were in complete control of the experimenter
b) Alternative Hypothesis
• Hypothesis opposite to H₀ and this hypothesis will be accepted if H₀ is rejected. It is also
known as the research hypothesis
c) Randomization
• Randomization is essential for a valid estimate of the experimental error and the
minimization of bias in the results.

Differentiate between inferential statistics and descriptive statistics.
Inferential statistics:
• Consists of generalizing from samples to populations, performing estimations and
hypothesis tests, determining relationships among variables, and making predictions

Descriptive statistics:



• Consists of the collection, organization, summarization, and presentation of data

Explain the meaning of the following terms: Variable (2 marks)
• A characteristic or attribute that can assume different values
Explain briefly the following terms:
Continuous quantitative variable (2 marks)
• Numerical and can be ordered or ranked
• Example: age, height, weight

State three (3) reasons for sampling (5 marks)
• To obtain samples that is unbiased
• Give each subject in the population an equally chance of being selected
• Easier to draw (only one random number is required)
• It distributes the sample more evenly over the listed population

Describe the following method of sampling designs:
a) Simple Random Sampling
Each item or element of the population has an equal chance of being chosen at each draw
E.g. one such method is to number each subject in the population

b) Systematic Sampling
Subjects are selected by using every kth number after the first subject is randomly selected
from 1 to k
E.g. suppose there were 2000 subjects in the population and a sample of 50 subjects were
needed

c) Stratified Sampling
Subjects are selected by dividing up the population into groups (strata), and subjects within
groups are randomly selected
E.g. suppose the president of two-year colleges want to learn how students feel about a certain
issue

d) Cluster Sampling
Subjects are selected by using an intact group that is representative of the population
E.g. suppose a research wishes to survey apartment dweller a large city. (10 marks)

List two (2) reasons why experiments should be designed.



• To estimate the experiment error
• To increases precision

What are the differences between preliminary experiment and critical experiment?
Preliminary Experiment:
• Investigator tries out a large number of experiments in order to obtain leads for future
work
• Most treatment will appear only once
Critical experiment:
• Investigator compares responses to different treatments using sufficient observations of
the responses to give reasonable assurances of detecting meaningful differences

Describe factors that affect an experiment due to non-uniformity of land. Describe two ways of
overcoming these factors. (10 marks)
Plot Size:
• Size of plots in field experiments has much to do with the accuracy, value and
importance of results
Plot shape:
• practical considerations (ease of management in the field)
• nature and size of variability (soil heterogeneity)
Block size and shape is governed by:
• plot size chosen
• number of treatments tested
• experimental design used
Number of replication:
• to measure experimental error
• to increase precision of an experiment (by reducing the std deviation of a treatment
mean)

Discuss in detail the prerequisite of a successful experiment. (10 marks)
Literature review:
• Every experiment is set up to provide answers to one or more questions
• Need a clear statement of the problem to be solved

Formulation of hypothesis:



STATEMENT OF OBJECTIVES may be in the form of:
• Questions to be answered
• Hypotheses to be tested
• Effects to be estimated

Selection of treatments:
Treatment (definition)
• A dosage of material or a method that is tested in the experiment
• Effect of treatment is to be measured and compared with other treatments
Experimental unit:
Unit of experimental material to which a treatment is applied:
• a single leaf
• a whole plant
• an area of planting Harumanis
• a pot in the greenhouse
• a flat in the field

Experimental material and number of replications:
• material should be representative of the population to which treatments will be tested
• The number of replications used in an experiment will depend on such factors as cost,
labor, variability of the test material, size of mean difference to be detected and the
level of significance to be used.

Selection of experimental design and types of experiments:
• Rule of assigning treatments to experimental plots

Completely Randomised Design (CRD)
• simplest layout
• treatments are assigned completely at random so that each experimental unit has the
same chance of receiving any one treatment
• appropriate for experiments with homogeneous experimental units

Randomised Complete Block Design (RCBD)
• most widely used experimental designs in agric. research
• used for simple experiments involving small number of treatments
• all treatments appear in each block
• data analysis is simple
• missing data easily handled



Latin Square Design (LSD)
• treatments are grouped into replicates in 2 different ways
• every row and every column of any square is a complete replication
• provide more opportunity than RCBD for reduction of errors by skilful planning
What are the sources of variation in field experiments? (3 marks)
Effect on interpretation of result and accuracy
• soil heterogeneity
• plant variability
• climatic variation

List and explain briefly the three sources of variation in field experiments. (6 marks)
Soil heterogeneity:
• field experiments should be made under uniform soil conditions
• differences in fertility may persists, under some conditions, for many years
• soils vary from meters to meters in texture, depth, drainage, moisture and available
nutrients
• soil heterogeneity is universal

Plant variability:
• genetic determination
• competition effects

Climatic variation:
• Climatic factors can cause differences in treatments effects from year to year
• Crop varieties are known to withstand extreme conditions (drought or excessive
moisture) better than others

How does soil topography influence the variation in soil productivity?
• directly or indirectly may influence the variation in soil productivity
• steep hillsides generally are not adapted for field experiments
• heavy rains may gully the field
• heavy rains carry fertilizers from one plot to another
• water may pond on low spots
• avoid land that are irregular in slope

List TWO (2) methods of overcoming soil heterogeneity. (2 marks)
• applications of organic manures to the previous crops



• the straw and tops on the land from previous crops
• variation in the amounts of commercial fertilizers applied to the previous harvested
trials

Describe the steps involved in uniformity trials to measure soil heterogeneity. (5 marks)
Uniformity trials:
• Plant an experimental site with a single crop variety
• Apply all cultural and management practices as uniformly as possible (all sources of
variability, except that due to native soil differences, are kept constant)
• Planted area is subdivided into small units of the same size (generally referred to as
basic units)
• Make separate measurement of productivity (e.g. grain yield)
• Yield differences between these basic units are taken as a measure of the area’s soil
heterogeneity

Describe the procedures available to reduce the effect of soil heterogeneity.
Slopes:
• Lower portions more fertile than high areas
• An ideal site is one that has no slope
• If level area not available – choose an area with a uniform and gentle slope because
such areas can be managed through use of proper blocking
Graded areas:
• Grading removes top soil from elevated areas and dumps it in the lower areas of a site
• Operation reduces the slope but results in an uneven depth of surface soil and at times
exposes infertile sub soils
• Differences persist for a long time
• Avoid an area that has had any kind of soil movement
Unproductive sites:
• A productive soil is an important prerequisite to a successful experiment
• Do not use an area with poor soil

Define treatment. Aside from having a control for comparison, list three (3) other things that
should be considered when choosing treatments. (5 marks)
Define treatment:
• A dosage of material or a method that is tested in the experiment
• Effect of treatment is to be measured and compared with other treatments
Things that should be considered when choosing treatments:



• There must be a control for comparison
• Other factors must be kept as constant as possible
• Choose a treatment range in a sequence
• Make sure that there is a strong basis for comparisons among treatments, e.g. urea,
ammonium as a source of nitrogen, etc
What does previous treatment means? How do researchers control the effect of previous
treatments?
Previous treatment:
• field or series of plots has been occupied by varietal or cultural tests that seriously
increase soil variability

Control the effect:
• one or more uniform crop should intervene before land is used again for such tests
• arrange the plots at right angles to direction of previous plots

Define replication and list two (2) objectives of replication. What are the factors that influence
the number of replications in an experiment? (8 marks)
Define replication:
• When a treatment appears more than once in an experiment, it is said to be replicated

Objectives of replication:
• To measure experimental error
• To increase precision of an experiment

Factors that influence the number of replications:
• Inherent variability of the experimental material
• Experimental design used
• Number of treatments to be tested
• Degree of precision desired

List three (3) things that need to be taken into consideration when choosing an experimental
area for research. (3 marks)
• Land should be as uniform as possible with respect to topography, fertility, subsoil and
previous soil management
• Perfectly level piece of land is undesirable coz water may pond on either side
• A slight slope is desirable on land to be irrigated
• When necessary to drain lands, the tile lines should be located so as to influence all
plots alike



• Tile lines should run across the plots rather than with them

List three (3) characteristics of a Latin Square Design.
• With the Latin Square design you are able to control variation in two directions
• Treatments are arranged in rows and columns
• Each row contains every treatment
• Each column contains every treatment
• The most common sizes of LS are 4x4 to 8x8

What is the difference between accuracy (ketepatan kejituan) and precision (bacaan yang
tepat)? What are three factors that will influence accuracy and precision of an experiment? List
THREE (3) methods of increasing accuracy and precision. (5 marks)
Accuracy:
• By using plot size method there is much to do with the accuracy, value and importance
of result
Precision:
• By using the number of replication there is increase precision of an experiment

Factors that will influence accuracy and precision:
Factors influencing the number of replications:
• Inherent variability of the experimental material
• experimental design used
• number of treatments to be tested
• degree of precision desired
Methods of increasing accuracy and precision:
• Plot size
• Plot shape
• Block size and shape
• Number of replication

Describe two (2) ways to minimize or eliminate competition effects in field experiments.
Removal of border plants:
• Effects of varietal competition, fertilizer competition and nonplanted borders are
usually shown on plants in outer row



• → → → exclude plants in outer rows from plot measurements
Grouping of homogeneous treatments:
• Ensure that adjacent plots are planted to varieties of fairly similar morphology or are
subjected to similar fertilizer rates

List and explain the types of competition effects that occur in field experiments. (5 marks)
Nonplanted Borders:

• areas between plots or around the experimental areas that are left without plants and
serve as markers or walkways

• these areas are generally wider than the area between rows or between plants in a row

• plants adjacent to these non-planted borders have relatively more space

• plants are exposed to less competition than plants in the plot’s centre

Varietal Competition:

• Trials involving different varieties of a given crop, adjacent plots are planted to different
varieties

• Varieties differ in their ability to compete, so plant in a plot will be subjected to different
environments depending upon location relative to adjacent plots – this effect is called
varietal competition

Fertilizer Competition:

• Plots with higher fertilizer application will be more vigorous and compete better for
sunshine and CO2

• Fertilizer could spread to the root zone of adjacent plot, putting the plot with higher
fertilizer at a disadvantage

List one (1) example of instances where mechanical errors can occur at the following occasion:
i) From the time the plots are laid out
Error in measurement



ii) During management and care of experiments
Used of miffed and unpure seeds

iii) During data collection
Error in measurement and characters and transcription
(3
marks)

What is experimental error and describe four (4) Sources of variation of experimental error in
field experiment.
Experimental error: (10 marks)
• Error that occurs in the execution of an experiment

Sources of variation of experimental error: check the answer first
In field experiments, mechanical errors can occur:
• from the time plots are laid out (error in measurement)
• during management and care of the experiment (used of mixed and unpure seeds)
• during collection of data (errors in measurement and characters & data transcription)
• mechanical errors are primarily human error
• mechanical errors cannot be effectively controlled by statistical techniques

Explain five (5) mechanical errors that frequently occur during the conduct of field experiments
and explain its method of prevention. (10 marks)
In field experiments, mechanical errors can occur:
• from the time plots are laid out (error in measurement)
• during management and care of the experiment (used of mixed and unpure seeds)
• during collection of data (errors in measurement and characters & data transcription)
• mechanical errors are primarily human error
• mechanical errors cannot be effectively controlled by statistical techniques
Furrowing for Row Spacing:
For row crops, any errors in row spacing are reflected as error in plot measurement
• Corn variety test
• Planting distance 0.75 m apart



• Four 5-m-long rows
• Plot size is 3 m x 5 m
• Spacing between rows incorrectly set at 0.80 m (instead of 0.75 m)
• Plot size is 3.2 m x 5 m

Selection of Seedlings:
• Seedlings raised in seedbeds and transplanted to experimental area
• More seedlings are usually grown than are actually required >>> allow some type of
seedling selection
• Usual practice
• use best looking seedlings first
• poorer seedlings are leftovers
• adequate procedure if few leftover seedlings
Thinning:
Procedure for directly seeded crops
• use a high seeding rate to ensure enough seeds will germinate
• number of plants per plot is reduced to a constant number (by thinning) several days
after germination

Transplant:
• number of seedlings should be uniform for transplanted crops
• easy for most vegetable crops (crops are large and easily separated from each other)
• for rice (seedlings are crowded) – number of transplanted seedlings vary from 2 – 5 per
hill

Fertilizer Application:
• not much of a problem to obtain uniform application of fertilizer if mechanical fertilizer
spreaders are available
• impossible to obtain uniformity when fertilizing by hand for a hectare of land
• simpler application for 10-50 m2
Usual procedure:
• weigh fertilizers in the lab
• put them in small paper bags / plastic sacks
• transport them to the field
• spread the contents of each sack uniformly over a small unit


Research technique

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Research technique

Ähnlich wie Research technique (20)

Mehr von Cikgu Marzuqi

Mehr von Cikgu Marzuqi (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Research technique