Prelab Quiz Flashcards
Controlled experiment
Scientists manipulate conditions and observe how this affects a measurable outcome
Can establish that one variable causes an outcome
Observational research
Some research questions can not readily be tested using controlled experiments for ethical or practical reasons, so we use observational studies to examine relationships between variables
Limitations of observational studies
Can not identify that one variable causes another
Can establish correlation between two variables
Exploratory research
Research without a clear hypothesis in mind
Leads to identification of variables to test for cause of an outcome
Hypothesis
Proposed explanation based on observations, prior scientific knowledge, prior experience, or critical reasoning
Must be testable
Should generate predictions of what would happen in experiments or what we should observe
Prediction
An expected outcome of a potential experiment or observation
What should be observed if a hypothesis is true
Rule of thumb for hypothesis
I expect to observe [prediction] because [hypothesis]
Independent variable
Variable that is manipulated in a controlled experiment to test whether it causes a change in an outcome
Dependent variable
Variable that is the outcome being measured in a controlled experiment
Dependent variables must be measurable/quantifiable
Controlled variables
Variables that are kept constant throughout an experiment
Where do you plot independent variable?
X-axis
Where do you plot dependent variable?
Y-axis
Positive control
Trial in an experiment that is expected to produce a strong positive result
Ensures that an assay is capable of producing a positive result
Example of positive control
All equipment/reagents are working
Negative control
Trial in an experiment that is expected to produce a strong negative (or minimal)result
Negative controls are useful as a BASELINE to compare results to
Often, this is the measure we would expect if the independent variable was not present