Hypothesis or research question
Seppo Karrila
Research Methodology
2017
Executive summary
• The Scientific Method starts with a
hypothesis, but in applied science it is often
easier to take the research direction as a
question
– Hypothesis tends to be yes/no or on/off type, but
the question can be “yes, but how much…”
• There are good and poor choices for that
direction, we summarize some guidance for
successful thesis project
Types of research
• Exploratory
– Mapping something on which there is little prior literature,
unpredictable results
• Testing-out
– Test prior knowledge outside its original scope (can use prior studies
as templates, just change some parameter or choice of material)
• Problem solving
– High risk, because if it is straightforward, then it is not a problem at
all… It is a problem if nobody knows what needs to be done.
– This can be an ultimate goal, but a thesis project must be doable – you
can’t promise to solve a problem, you can test a candidate solution
• Theory only
– Normal in math, theoretical physics, theory of fluids, thermodynamics,
etc. MS level usually is about explaining existing theories,
demonstrating learning and understanding. PhD expects new
contributions.
Suitable as “safe” projects
• Exploration of an inventive idea
– Combining existing tools in a novel way, seeing what happens
• Testing-out
– Use the prior publication as template for plan and analysis,
instead of materials A & B (published) you use C & D.
• Trouble with safe projects
– If they are too safe and predictable, then any student will
perform about similarly. No room for an exceptional student to
show abilities.
– Need to add a component where the student has some
challenge… or provide opportunities to expand from initial plan.
Extension and replication
• Testing-out is an example
– Replicate prior work with slight changes, that
extend outside earlier results (this is also called
approximate replication)
• Conceptual replication
– Test if earlier findings can be corroborated by a
different approach (change methods used)
– Particularly fit with novel measurement devices or
techniques – compare new estimates to “old”
measurements
Elastic questions are good
• The idea is that the project can be shrunk or
expanded, as necessary – must have several
points where it could stop (because of time limit)
• This again gives safety, but allows a fast student
to go far, and a slower student to finish in time
• It is common that answering one question leads
to another question
– To have that planned ahead of time can be difficult
Hypothesis vs. question
• In fundamentals of science, hypotheses could be
used to test the “axioms” needed for theory
– We can leave that to the next Einstein
– Hypothesis tends to have on/off or yes/no character
– Often you already know “yes, this affects”, and the
question is “how much, is this knowledge useful?”
• So, for planned research it is typical to pose a
question (or a few of them)
– How much can we improve extraction yield by
sonicating? Should it be used before or during
extraction?
A good question is
• Up-to-date
• Has originality or novelty
• Is important or at least interesting
• Is small and precise
• Is practically testable
Recall the approach to planning of
experiments
• List all factors that can affect your results
• To get a short list, remove some by selecting
– This gives the scope of your study
• Choose the main manipulated variables
– This means your hypothesis is that these are the most useful or
most influential ones
– If you have many variables, test with Plackett-Burman to
determine the most important ones. Perhaps continue to
optimize these, with another set of designed experiments.
• What are the measurements?
– Targeted output of course
– Also disturbances that you can’t control, i.e. factors not
eliminated by scope and not manipulated. Include in statistical
analysis…
Why only main factors are
manipulated?
• Usually you want to have
– Two levels per factor, to select which factors are
unimportant and can be ignored
– Then three levels per factor, to see curved responses (two
points only define a line)
• Two manipulated factors would give 3*3 = 9
experiments (without replicates)
• Three would give 3*3*3 = 27, four would give 81, etc.
– You have limits on time and cost, so at most 3 manipulated
factors in practice
– With clever statistical designs the number of experiments
comes down from full factorial design
The experimental design is coupled
with statistical analysis
• Statistics can show
– Significant differences between alternatives, and
effect size of the choice
– Regression models for continuously manipulated
variables (not only alternative levels, but you can
choose a value from, say, 1.0 to 4.5), or for
measured disturbances
– Models that help find an optimum (maximum or
minimum), so-called “response surface models”
In a research proposal
• If you propose specific experiments, you should
also explain the analysis and what you expect out
of it
– You have a goal to answer some question, the
combination of experiments and analysis is how you
reach that goal
• You will need to estimate time and cost of the
experiments also: somebody must have the
money or budget you need
• Next presentation is about the research proposal
Reference
• Parts of the discussion were influenced by
Chapter 2 in Lowe: A first textbook of research
methodology… , 2016
Available online at
www.scientificlanguage.com

L3 hypothesis or research question

  • 1.
    Hypothesis or researchquestion Seppo Karrila Research Methodology 2017
  • 2.
    Executive summary • TheScientific Method starts with a hypothesis, but in applied science it is often easier to take the research direction as a question – Hypothesis tends to be yes/no or on/off type, but the question can be “yes, but how much…” • There are good and poor choices for that direction, we summarize some guidance for successful thesis project
  • 3.
    Types of research •Exploratory – Mapping something on which there is little prior literature, unpredictable results • Testing-out – Test prior knowledge outside its original scope (can use prior studies as templates, just change some parameter or choice of material) • Problem solving – High risk, because if it is straightforward, then it is not a problem at all… It is a problem if nobody knows what needs to be done. – This can be an ultimate goal, but a thesis project must be doable – you can’t promise to solve a problem, you can test a candidate solution • Theory only – Normal in math, theoretical physics, theory of fluids, thermodynamics, etc. MS level usually is about explaining existing theories, demonstrating learning and understanding. PhD expects new contributions.
  • 4.
    Suitable as “safe”projects • Exploration of an inventive idea – Combining existing tools in a novel way, seeing what happens • Testing-out – Use the prior publication as template for plan and analysis, instead of materials A & B (published) you use C & D. • Trouble with safe projects – If they are too safe and predictable, then any student will perform about similarly. No room for an exceptional student to show abilities. – Need to add a component where the student has some challenge… or provide opportunities to expand from initial plan.
  • 5.
    Extension and replication •Testing-out is an example – Replicate prior work with slight changes, that extend outside earlier results (this is also called approximate replication) • Conceptual replication – Test if earlier findings can be corroborated by a different approach (change methods used) – Particularly fit with novel measurement devices or techniques – compare new estimates to “old” measurements
  • 6.
    Elastic questions aregood • The idea is that the project can be shrunk or expanded, as necessary – must have several points where it could stop (because of time limit) • This again gives safety, but allows a fast student to go far, and a slower student to finish in time • It is common that answering one question leads to another question – To have that planned ahead of time can be difficult
  • 7.
    Hypothesis vs. question •In fundamentals of science, hypotheses could be used to test the “axioms” needed for theory – We can leave that to the next Einstein – Hypothesis tends to have on/off or yes/no character – Often you already know “yes, this affects”, and the question is “how much, is this knowledge useful?” • So, for planned research it is typical to pose a question (or a few of them) – How much can we improve extraction yield by sonicating? Should it be used before or during extraction?
  • 8.
    A good questionis • Up-to-date • Has originality or novelty • Is important or at least interesting • Is small and precise • Is practically testable
  • 9.
    Recall the approachto planning of experiments • List all factors that can affect your results • To get a short list, remove some by selecting – This gives the scope of your study • Choose the main manipulated variables – This means your hypothesis is that these are the most useful or most influential ones – If you have many variables, test with Plackett-Burman to determine the most important ones. Perhaps continue to optimize these, with another set of designed experiments. • What are the measurements? – Targeted output of course – Also disturbances that you can’t control, i.e. factors not eliminated by scope and not manipulated. Include in statistical analysis…
  • 10.
    Why only mainfactors are manipulated? • Usually you want to have – Two levels per factor, to select which factors are unimportant and can be ignored – Then three levels per factor, to see curved responses (two points only define a line) • Two manipulated factors would give 3*3 = 9 experiments (without replicates) • Three would give 3*3*3 = 27, four would give 81, etc. – You have limits on time and cost, so at most 3 manipulated factors in practice – With clever statistical designs the number of experiments comes down from full factorial design
  • 11.
    The experimental designis coupled with statistical analysis • Statistics can show – Significant differences between alternatives, and effect size of the choice – Regression models for continuously manipulated variables (not only alternative levels, but you can choose a value from, say, 1.0 to 4.5), or for measured disturbances – Models that help find an optimum (maximum or minimum), so-called “response surface models”
  • 12.
    In a researchproposal • If you propose specific experiments, you should also explain the analysis and what you expect out of it – You have a goal to answer some question, the combination of experiments and analysis is how you reach that goal • You will need to estimate time and cost of the experiments also: somebody must have the money or budget you need • Next presentation is about the research proposal
  • 13.
    Reference • Parts ofthe discussion were influenced by Chapter 2 in Lowe: A first textbook of research methodology… , 2016 Available online at www.scientificlanguage.com