The Principles of Experimental Research

391 Pages·2006·4.653 MB·English

by  K. Srinagesh (Auth.)

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I have had the opportunity of participating in many, and
watching even more, research projects, ranging from industrial
Research and Development (R&D) to Ph.D. dissertations.
Most of these, when experimental, are still one-factor-at-a-time
experiments. In spite of the fact that such luminaries sa Fisher,
Taguchi, and Deming have demonstrated the irrelevance of
one-factor-at-a-time experiments, it seems sa though these peo-
ple never existed. In undergraduate education, almost sa a rule,
Probability and Statistics si not taught, with a conspicuous
exception: in psychology. Even where "advanced mathematics"
and "applied mathematics" are considered essential, for example
in engineering, Probability and Statistics si ignored. This si a
pitiable lack of proportion.
It si fairly common that college undergraduates have to do a
capstone project in their senior year. Many of their projects
involve experimental work. That si where the fixing has to be
done. The students should be made aware that one-factor-at-a-
time experiments are most often unjustified. To do multi-factor
experiments, the students should have been taught Probability
and Statistics before the senior year. Equally important for an
experimenter~no matter at what level--is to be familiar with
the basics of logic, for experimentation si logic in action. To real-
ize that this si so, the experimenter should be exposed to the
basics of what si known sa the "Philosophy of Science."
Thus, this book si a combination of Philosophy of Science,
Logic, Probability and Statistics, and Designing and Analysis of
Experiments~all these aspects blended at the level suitable for
upper level undergraduates or first year graduate students. It si
my experience, and I submit that no undergraduate education in
iivx
iiivx
sciencemeither theoretical or applied---should be considered
complete without a full-fledged course on topics like those pre-
sented in this book. Even more so, it si true for students in Mas-
ters and higher level studies. And, industrial R&D researchers (I
have been one for six years) who have not had a course like this
before suffer from an insidious professional deficiency.
This book si not for professionals or advanced students in
statistics, logic, and philosophy of science. It si for students of sci-
ence, theoretical and applied. Within their domain of interest,
there si need to gain a working familiarity with the above-men-
tioned disciplines, but there si a regrettable lack of time to study
any of these in depth. Books are available in plenty: books writ-
ten by statisticians for other statisticians, by logicians for other
logicians, by philosophers of science for other philosophers. But
such books will not serve the need of science students in colleges,
or the beginners in experimental research, and hence this book.
Undergraduate instructors using this book have ample scope to
emphasize the topics of interest to suit the level and need of their
students. More mature and senior readers should be able to read
the book on their own. Selective reading from books listed in
chapter-end bibliographies help them in further progress.
During the long growth period of this book, I have had the
good fortune of getting generous help from many persons. My
friend, Dr. Sherif 1E WaHl, stood by me with advice at all stages.
My colleague, Prof. Noreen Cleffi read every one of these chap-
ters, and made many corrections. Mr. Manny Pereira, Ms. Fran-
cine Gilbert and Mr. Rajendra Desai helped me in preparing the
manuscript. Ms. Paige Gibbs searched several library resources
for me. Mr. Joel Stein of Elsevier Science advised me in format-
ting the book. And, without the help of my wife, Prof. Sampurna
Srinagesh, I would be still reading through mysterious words,
and still searching for missed references, missed manuscripts, and
missed books. I am grateful to all these people. I would be much
obliged to those who find this book useful, to tell me .os Just sa
much, I would be obliged to those who would indicate the
defects and deficiencies in this work.
I
Experimental Research in Science: Its
Name and Nature
Does it contain any abstract reasoning concerning quantity or num-
?reb No. Does it contain any experimental reasoning concerning
matter of fact and ?ecnetsixe No. Commit it ot the flames, for it nac
contain nothing but sophistry and illusion.
David Hume
Experimental research si the theme of this book. This introduc-
tory chapter attempts to delineate the scope of the book. The
research referred to here si limited to that in science and its
byproduct, technology. This demands a closer look at the word
"science" itself, followed by the need to define the activity
broadly accepted sa scientific research. The so-called theoretical
research in science(s) si out of our bounds. We also need to steer
past quite a few activities colloquially referred to sa "research-
ing." Our concern si limited only to experimental research in
science. While noting that those who do and enjoy research for
its own sake are exceptions, this chapter points out some charac-
teristic features in the working lives of career researchers, who
are the rule.
I.I Defining Science
Attempts to define the word "science" offer many variations,
none of which may be complete or fully satisfactory. The word
"science," a derivative from the Latin scientia, simply means
knowledge. We know that any person with great knowledge si
not necessarily a scientist, sa we currently use the word. On the
other hand, the word "philosophy," a derivative from Greek,
2 I~ Defining ecneicS
means love of wisdom. When combined with the word "nature"
to form "Natural Philosophy," the phrase seems to refer to the
knowledge of nature; it si more specific. Until fairly recently, sci-
ence was, indeed, referred to as natural philosophy. The full title
of Isaac Newton's monumental work si Mathematical selpicnirP of
Natural .yhposolihP
For reasons not easy to trace, the name natural philosophy
was dropped for the preferred name, science. The intellectual dis-
tance between science and philosophy, for a time, increased, until
about the early part of the twentieth century, when some of the
best known scientists started philosophizing on such concepts as
space, time, matter, and energy. Philosophers, in turn, found a
new topic ripe with possibilities: the philosophy of science.
Returning to the phrase "natural philosophy," the word "natu-
ral" simply signifies nature. Thus, science may be understood to
indicate curiosity about or knowledge, even love, of nature. If sci-
ence si the study and knowledge of nature, we mean nature minus
man. Man and nature are thus placed as dipoles, with man at one
polarity taking a position from which he can study nature for play,
curiosity, admiration, or even exploitation and gain. Nature, on
the other hand, "just lies there," like an animal caged in a zoo, or
worse, like a cadaver for a student's study by dissection.
As if to protest such harsh statements, in nature we have not
just the inanimate part, but the animate part as well, and the
above statement may be justified only for the inanimate part.
The study of the animate part is broadly covered under biology
with various specialties. The medical sciences, as a group, are a
good example of where the polarity of man and nature gets
blurred, since man himself with life--is the subject of study,
combining other sciences, such as physics, chemistry, and biol-
ogy. What about technology? Much of the admiration accorded
to science is derived from its accomplishments through its deriv-
ative, technology. Like a full-grown son beside his aging father,
technology stands tall and broad, dependent yet defiant. With
this attempt to define science broadly, we may briefly look at
some definitions available:
"Comprehension or understanding of the truths or facts of
any subject" (Webster's Dictionary).
1.2 Science: Play or Profession? 3
"The progressive improvement of man's understanding of
Nature" (Encyclopedia Britannica).
"IThe study of those judgments concerning which univer-
las agreement can be obtained" (Norman Campbell, What
sI ?ecneicS (New York, NY, Dover, 1953).
"Essentially a purposive continuation of... what I have
called common knowledge, but carried out in a more sys-
tematic manner, and to a much higher degree of exactitude
and refinement" (E. W. Hobson, ehT Domain of Natural
ecneicS (New York, NY, Dover, 1968).
These being only a few of the many definitions offered for sci-
ence, we venture to add one more: Science si the activity directed
toward a systematic search for, or confirmation of, the relations
between events of nature.
1.2 Science: Play or Profession?
Apart from the definition(s), it si to be understood that science,
per ,es si not the theme of this book. There are many books and
articles devoted to the definition, delineation, and explanation of
what science ,si to discussing what its aims and activities should
be, and even to philosophizing about what its limitations are.
The relevance, however, of science to this book si that science,
unlike subjects known sa "liberal arts," si very much associated
with experimental research.
In terms of experiments, scientific research may be broadly
classified into two categories with a slight overlap: (1) theoretical
research and (2) experimental research. Some of the greatest
works in physics, for example, quantum mechanics, are the out-
come of theoretical research. The work of great theoretical scien-
tists not only solve many scientific puzzles but also create new
visions through which hitherto unknown relations between
events can be predicted, leading to new experiments.
Several raw materials, heaped together or scattered here and
there, do not make a house. It si the work of a builder to create a
house out of these raw materials. In terms of science, theories are
like finished houses, and experimental findings leading to some
generalizations are more like house-building materials. Whereas
I Chapter I
4 1.2 Science: Play or Profession?
the works of Michael Faraday are experimental, those of James
Maxwell are theoretical. Some of the greatest figures in physics
have been theoretical scientists: Ludwig Boltzman, Neils Bohr,
Werner Heisenberg. Scientist of that caliber, who also happen to
be great experimental researchers, are rather few: Isaac Newton,
Errico Fermi, Henry and Lawrence Bragg. But a large number of
researchers, not only in physics but in other areas of science sa
well, are experimental researchers.
This si not to belittle the value of experiments. In fact, no the-
ory si valid until it passes one or more crucial tests of experi-
ments. In engineering and technology also, some works lay claim
to being theoretical; however, considering their limited domains,
albeit extensive applications, they are more in the nature of gen-
eralizations based on empirical data.
As a side issue, si the work of Charles Darwin theoretical or
experimental? It si true, Darwin spent time "in the field" collect-
ing a lot of new "data" on his well-known expedition to the
sogapali~G Islands. But his work, embodied in writing, consisted
of fitting together the many pieces of the puzzle to form a fin-
ished picture, which came to be known sa the Theory of Evolu-
tion. Experimental? Maybe. Theoretical? .seY
This far we have looked at science sa an activity. Looking at
the actors in this drama known sa science si even more interest-
ing. Leonardo da Vinci si acclaimed sa a great scientist; yet, his
fame rests on many unfinished works. His dependence on experi-
ment and observation rather than preconceived ideas marks him
sa the precursor of the experimental researcher. Curiosity led him
into many fields of inquiry: mechanics, anatomy, optics, astron-
omy. Being primarily an artist, possibly he did not depend for his
living on scientific activities.
Galileo Galilei's interest in mechanics and astronomy, Johannes
Kepler's in planets, Gregor Mendel's in mutation of plant seeds,
Ivan Pavlov's in conditioning dogs: lla have something in com-
mon, namely curiosity to observe the way these segments of nature
operate. These men, quite likely, did not earn their livings by
means of their scientific interests either. It si in this sense that
Ervin Schrodinger, in his book ,ecneicS Theory and Man (1957),
equates science with the arts, dance, play--even card games, board
games, dominos, and riddles~asserting that these activities are the
result of surplus energy, in the same way that a dog in play si eager
1.3 Science and Research 5
to catch the ball thrown by his master. "Play, art and science are
the spheres of human activity where action and aim are not sa a
rule determined by the aims imposed by the necessities of life."
The activity of science has changed considerably since the
times of Pavlov or Mendel, even since the times of Schrodinger.
He writes, "What si operating here si a surplus force remaining at
our disposal beyond the bare struggle for existence; art and sci-
ence are thus luxuries like sport and play, a view more acceptable
to the beliefs of former centuries than to the present age." In the
present age, the activity of science si no more a luxury; it has
become a need, though more collectively than individually. An
individual, even in a scientifically advanced country, may not be
cognizant of the results of science in his or her daily life; nonethe-
less, his way of life, even relative to bare necessities, si vastly dif-
ferent from that of humans even 200 years ago. The difference,
more than anything else, si attributable to the fruits borne by sci-
ence. The percentage of people now involved in activities that
can be considered scientific si very large compared to that of 200
years ago. Further, science, which was more or less the activity of
isolated, private individuals, si now more the activity of an "orga-
nization man." An individual privately working out a theory or
conducting an experiment or inventing a device si a rare excep-
tion. Thomas Edison si said to have taken many patents before
establishing the General Electric lab. But since his time, about a
century ago, the so-called scientist now belongs to an organiza-
tion. In this way, science si neither a luxury nor an activity of sur-
plus energy. It si a full-time job, a professional career for many
persons; it si no longer play.
1.3 Science and Research
The word "research," like many others, has acquired a wide cur-
rency over the past several decades. Relatively few people con-
ducted research in the first half of the twentieth century. Those
who were known to be doing research were looked upon sa
belonging to an elite class, often shrouded in mystery, not unlike
the FBI agents portrayed in popular movies. In the imagination
of the common person, researchers belonged to a secret society,
the initiation into and the ideal of which were guarded secrets.
Not any more. Elementary school children now ask their parents
I Chapter I
6 3.1 ecneicS dna hcraeseR
for rides to libraries or museums because they have to "do some
research" on a project given by their teacher. If we need a book
from the library and that particular book si not found in the list
or on the rack, the librarian says, on your request for help, that
she or he "needs to do some research." Finding a particular poem
needs research; so does finding a music album, or a particular
brand, style, or size of shoes.
With the expanding influence of consumer goods on the lives
of common people, market research has acquired great power.
Firstly, the products that members of society consume, be they
houses, cars, items of clothing, or sunglasses, are the outcomes of
research. Secondly, the various subtle and sophisticated processes
of persuasion~the brand names by which a product si called, the
faces that flash, the music that plays during a commercial, the
pictures of heroes, stars, or muscle men on packaging~are all
subject to market research.
The service industry si just sa much shaped and controlled by
research. The kind of plays, movies, or TV shows that are likely
to become popular (hence, profitable) are not guessed and gam-
bled on any more. Entrepreneurs intending to start a new prod-
uct a few decades ago needed to do the familiar "market survey."
Now, they go to specialty companies that "do research" to find
the answer to fit the client's requirement. Lawyers searching for
precedents, doctors looking for case histories, accountants look-
ing for loopholes to minimize taxes: all engage in matters of
research. Though one may question the accuracy of the word
"research" in these contexts, the word, of course, si free for all.
But we want to point out that research, sa discussed in this book,
si meant to be scientific research in its broadest sense. Accord-
ingly, ornithologists observing the nesting habits of the peregrine
falcon, pharmacologists trying to reduce the side effects of a
drug, zoologists planning to clone a camel: all these, besides hun-
dreds of other activities, may be considered academic, technical,
or scientific research.
Further effort to delineate the scope of this book calls for a
bifurcation, somewhat overlapping, between research activities
that are scientific in nature and those that are not; this book
deals only with the former, meaning, research in those areas that
are conventionally considered "science." Thus, although several
thousand Ph.D. dissertations being written throughout the
1.4 Varieties of Experimental Research 7
world in the areas of philosophy, political science, literature, and
so forth, are research efforts, these, for our purpose, offer mar-
ginal interest. And even within science, this book deals only
with those research works that are experimental in nature. This
distinction requires that we clarify the phrase "experimental
research" even further.
4.1 Varieties of Experimental Research
To experiment si to try, to look for, to confirm. A familiar exam-
ple may make the meaning clear. After getting ready in the morn-
ing to go to the office, I look for the keys. I can't find them. I am
mildly agitated. Thoughts of not getting to the office, of not get-
ting the notes I wrote yesterday, of going late or empty-handed to
class, and so forth, run quickly through my mind. But I know the
first thing I need to do si look for my keys. I run up again to my
bedroom and look in the same chest of drawers where I keep
them every night. Not there. I look in the next drawer. Not there
either. Then, I recollect that I was watching TV last night. I go
into the TV room and look on the TV table and places near
about. Not there. Then, I think of the clothes I wore yesterday. I
go to the closet, recollect what I wore, and search the pockets.
Not there. Did I, by any chance, leave them in the car when I got
out of it yesterday? I look through the locked door of the car. Not
there. Then, I remember that I needed the keys to lock the door;
so, I decide, because the doors are locked now, there si no chance
that the keys are inside the car. I go back into the house and ask
others in the family if any of them have seen my keys. They start,
half-heartedly, looking for them. In the meanwhile, I go up to
the bedroom, rehearse in my mind--even partly, physically and
orally~how I came into the house yesterday, where and how I
keep my briefcase, where and how I removed my jacket and
shoes, how I was called to eat dinner soon after, how I did not
fully change my clothes before going to the table, and so forth. I
go through the places involved, look at all surfaces on which I
could have placed the keys, step by step in sequence. I even open
the refrigerator and look inside~just in case. My frustration, of
course, is mounting steadily.
At this stage, the reader may object that this si all searching;
where si the experiment? Indeed, it si searching, but searching
I Chapter I
8 4.1 Varieties of Experimental hcraeseR
with a difference. The difference is that the search is not haphaz-
ard; it is not arbitrary. Frantic though it appears, it is systematic;
it is organized. It was done with one question in mind all the
time: Can my keys be here? The search is not extended every-
where: to the bathrooms, the attic, the basement, the backyard,
or even to other bedrooms. It is done only in places where the
keys are likely to be. The circumstances that could cause them to
be in selected places are thought about. To use a more precise lan-
guage, it is a search directed by one or more hypotheses.
If my boy wants to collect seashells, I will take him to the sea-
shore, not to the zoo. If he wants to collect pinecones, I advise
him to wait until late fall, then to go and look under pine trees,
not under any tree in the park. Every parent, with some sense,
does the same. Primitive as they seem, these are logical decisions:
to search with a question in mind and to do so at a time and place
and under the circumstances likely to yield a favorable answer.
I am aware that these examples are not adequate in strength to
reach the textbook definition of "experiment," but these are
experiments, nonetheless. Very famous scientific works, like the
discovery of the planet Neptune in 1846, which was hailed as one
of the greatest achievements of mathematical astronomy, not-
withstanding all the work it involved in mathematics and astron-
omy, is eventually a search. Many theoretical calculations were
obviously needed to direct the search at a particular location in
the vast sky at a particular time. But is it far-fetched to call the
search for the object itself an experiment?
If the above si an example of a deliberate search, backed by an
expectation, there are instances in the world of science in which
unexpected happenings led to discoveries of monumental scale.
Wilhelm Roentgens discovery of X-rays and Alexander Fleming's
discovery of antibiotics are, to outsiders, just accidents. But such
accidents can happen only to those who are prepared to perceive
things that most of us do not. The culture of the mind of those
scientists was such that they could decipher meaning in these
"accidents"; they could expect answers to questions they were
prepared to ask, even if they had not consciously asked them yet.
The preparation of their minds embodies the question; the acci-
dents, the answers. The accidental discoveries, subject to further
confirmation or variation, become part of science.