Discussion 4

Which is better, green house or open space for growth

Are tomatoes produced in greenhouse of better quality when compared with the ones produced in
open space?
Respond to this report using the hypothesis given. Follow the correct format.
This paper should be two full pages long written in paragraphs that range around 100 words each.
Use subheadings where necessary. Format your paper in APA
Lab #1
BIOL 321
Qatar University
College of Arts and Sciences
Department of Biological and Environmental Sciences
Principles of Environmental Biology
Lab Record No. 1
————————————————————————————————————–
Scientific Hypothesis and Experimentation
PURPOSE
This lab serves to initiate and provide a guideline for the student conducting an experiment about Environmental
Sciences.
Students will initially develop a claim (non-scientific) and learn how to use evidence to support a claim. They
then are provided with a scientific research question for which they need to make a claim supported with
evidence from a monitoring or an experiment.
Results of the procedure will be simulated and based on their results, they will discuss their “findings” and draw
conclusions and report their results.
Final results will be compiled in a report discussing the obtained outcomes of the experiment.
OVERVIEW
Hypothesis generation and testing
Experimental design / Sampling design
Environmental experiment, results and conclusions?
At the lab:
1. Make a claim based on a provided “research question” around a particular popular topic (e.g., are cucumber
produced in Qatar of better quality when compared with the ones imported?), any other question?
2. Experiment or monitoring? What to measure (i.e. response parameters)
3. Which design?
4. Simulate/generate results ☺
5. Use evidence to support your claim: your conclusions
6. Develop a working understanding of key terms like: Research Question, Claim, Experiment, Measurement,
Data, Evidence, Explanation, Argument
7. Write your report with previous outcomes (1-6)
Good work!
Scientific Hypothesis and
Experimentation
BIOL321 – Lab#1
Today’s talk
• Hypothesis generation
• Hypothesis testing
• Elements of good experimental design
• Tips on experimental design
• What comes after the experiment?
• Activity and lab report
Some different types of
scientific work
• Measuring things (e.g. rainfall)
• Making things (e.g. expressing proteins in
bacteria)
• Finding out how the universe operates
(e.g. testing hypotheses about biology,
physiology, disease)
Some definitions
• Experiment: action or operation
undertaken in order to discover something
unknown, test hypothesis, etc.!
• Science is nothing but trained and
organised common sense, differing from
the latter only as a veteran may differ from
a raw recruit (Thomas Huxley)
Stages in designing and
executing a set of experiments
• 1. Formulate a hypothesis.
• 2. Design and execute a monitoring, an
experiment or series of experiments to test
(disprove) the hypothesis.
• 3. Analyse and interpret the
monitoring/experimental results.
• 4. Reject hypothesis, or refine and re-test,
or provisionally accept.
• 5. Report the conclusions.
Formulating the hypothesis
• Hypothesis: supposition made as a basis
for reasoning, or as a starting point for
investigation.”
• The great tragedy of Science – the slaying
of a beautiful hypothesis by an ugly fact!
(Thomas Huxley)”
literature / own data / discussion /
conference / supervisor
the first clever bit…..
Literature search / discussion
must be unambiguous write it down!
another clever bit…..
Stages in designing an
experiment
• 1. Have a hypothesis to test. Where possible we
try to test hypotheses by intervention, rather than
by correlation.
• 2. Decide what treatments/interventions to apply
and what outcomes to measure.
• 3. Randomly assign “subjects” to experimental
groups.
• 4. Decide on intervention / treatment schedule: e.g.
order, frequency, dose.
• 5. Decide on schedule of observations /
measurements.
Causal Relationships and Associations
For example:
• Across countries per capita ice cream
consumption is associated with per capital
television ownership. Is this a causal
relationship or an association?
• Statistics (of observations) can tell you if
there is an association between two
variables but not if that is causal.
Elements of good experimental
design
• 1. Discrimination: should test only one
hypothesis.
• 2. Replication: enough subjects to allow
for statistical tests of significance.
• 3. Controls: negative and positive.
• 4. Free of observer bias.
• 5. Measurements – accurate and precise.
• 6. Efficiency and practicability.
Discrimination: should test only
one hypothesis
• Example:
• Observation: substance X does not dissolve in
water at room temperature.
• Hypothesis: substance X will dissolve under
alkaline conditions.
• Experiment: place substance X in NaOH pH 9.0,
heat to 50º C for 1 hour.
• Outcome: X dissolves.
• Has the hypothesis been properly tested?
Dependent and Independent Variables
Dependent variable – what you’re trying to explain
Independent variable – what we think causes changes in the
dependent variable.
Independent Variable ð Dependent Variable
Hypothesis
Replication: enough subjects to allow
for statistical tests of significance
• This is the realm of statistics!
• At the outset you can calculate how many
subjects you need in each experimental
group to achieve a certain level of
statistical significance when comparing
data sets.
Controls: always negative controls
• Example:
An animal is injected with a test drug
dissolved in saline twice per day.
The negative control should be……..?
Free of observer bias
• Random assignment of subjects to
experimental groups.
• “Blinded” experiments, particularly when
the measurement is subjective.
Measurements: accurate and
precise
• Accuracy: does the method give you an
unbiased value on average?
• Precision: does the method give you a
reproducible result on repetition?
• Common mistake: if a balance reads to
the nearest gram, don’t express data
means and errors to the nearest 0.1 gram.
Efficiency and practicability
• Ethics
• Time
• Cost
• Expertise
• Availability of reagents
Tips on experimental design
• Consider possible sources of experimental error
• Try to obtain “hard” data, i.e. numerical readouts, and avoid subjectivity
• Build in a “dry run” for procedures you haven’t
done before – at the very least, don’t perform a
very large, complex experiment first up
• Write up a thorough account of your reasoning,
calculations, etc.
• Write a simple protocol (e.g. a flow chart) to
which you can refer “on the day”
What next
• Apply appropriate statistical tests (and don’t confuse
“replicates” with “subjects”)
• Plot your data: line charts, histograms; raw data,
“%control”
• Is the reproducibility satisfactory?
• The problem of “outliers” – data cannot be rejected
because we don’t like what they say (use the ±2SD
method)
• Repeat the experiment, if feasible
• How does the hypothesis look now?
• Discuss your data with others
• Report on your data and conclusions
Activity #1:
Hypothesis testing
Lab #1
BIOL 321
Qatar University
College of Arts and Sciences
Department of Biological and Environmental Sciences
Principles of Environmental Biology
Lab Record No. 1
————————————————————————————————————–
Scientific Hypothesis and Experimentation
PURPOSE
This lab serves to initiate and provide a guideline for the student conducting an experiment about Environmental
Sciences.
Students will initially develop a claim (non-scientific) and learn how to use evidence to support a claim. They
then are provided with a scientific research question for which they need to make a claim supported with
evidence from a monitoring or an experiment.
Results of the procedure will be simulated and based on their results, they will discuss their “findings” and draw
conclusions and report their results.
Final results will be compiled in a report discussing the obtained outcomes of the experiment.
OVERVIEW
Hypothesis generation and testing
Experimental design / Sampling design
Environmental experiment, results and conclusions?
At the lab:
1. Make a claim based on a provided “research question” around a particular popular topic (e.g., are cucumber
produced in Qatar of better quality when compared with the ones imported?), any other question?
2. Experiment or monitoring? What to measure (i.e. response parameters)
3. Which design?
4. Simulate/generate results ☺
5. Use evidence to support your claim: your conclusions
6. Develop a working understanding of key terms like: Research Question, Claim, Experiment, Measurement,
Data, Evidence, Explanation, Argument
7. Write your report with previous outcomes (1-6)
Good work!