Physics #11 Flashcards
scientific method
a set of steps that defines the appropriate order of events to structure and carry out an experiment
experimentation data collection
involves manipulating and controlling variables
observation data collection
involves no changes in the subject’s environment
Put the steps of the scientific method in the correct order: publish collect new data gather data and resources analyze the data generate a testable question verify results form a hypothesis interpret the data and existing hypothesis
generate a testable question gather data and resources form a hypothesis collect new data analyze the data interpret the data and existing hypothesis publish verify results
hypothesis
the proposed explanation or proposed answer to our testable question
what format do hypotheses usually follow?
if-then statements
what are the 5 questions asked using the FINER method to determine if a research question will add to the body of scientific knowledge in a practical way and within a reasonable time perioid?
- feasible: gather materials, subjects, time, financial constraints
- interesting: is there utility in the answer
- novel: has the question already been asked
- ethical: are there any ethical violations associated with answering the research question
- relevant: will it effect people outside of the research field too
In order to make generalizations about our experiments, we must make sure that the outcome of interest would not have occurred without our intervention, therefore we use ____
controls
positive control
ensure a change in the dependent variable when it is expected
ex: in testing the development of a new assay for detection of HIV, administering actual HIV to the assay should result in a positive result
negative control
ensure no change in the dependent variable when no change is expected
Ex: in testing the development of a new assay for detection of HIV, known non-HIB samples used in the assay should result in a negative result
placebo effect
an observed or reported change when an individual is given a sugar pill or sham intervention.
in basic science research, we manipulate the ______ and measure or observe the ____
independent variable
dependent variable
when is a relationship said to be causal?
when a change in the independent variable always precedes a change in the dependent variable, and when the change in the dependent variable does not occur in the absence of the experimental intervention.
On a graph, the independent variable belongs on the ____ axis and the dependent variable belongs on the ____ axis
x axis
y axis
accuracy/validity
the ability of an instrument to measure a true value
Ex: accurate scale should measure a 170 pound person as 170 pounds
precision/reliability
the ability of the instrument to read consistently or within a narrow range.
because bias is a systematic error in data, only an ______ tool will introduce bias
inaccurate
controls in experiments are used to establish _____
causality
randomization
the method used to control for differences between subject groups in biomedical research.
a proper randomization algorithm will be equivalent to a ____
coin toss or die roll
blinded
the subjects or investigators do not know which group certain individuals are in
sinlge-blind experiments
only the patient or the assessor is blinded
double-blind experiments
the investigator, subject, and assessor all do not know the subject’s group
discuss binary, continuous, or categorical variables
binary: yes or no
continuous: scale: cardiac output
categorical: state of residence
confounding variable
In statistics, a confounder is a variable that influences both the dependent variable and independent variable, causing a spurious association.
what are the 3 types of observational studies in medicine?
cohort, cross-sectional, case-control
cohort studies
subjects are sorted into groups based on differences in risk factors (exposures) and then assessed at various intervals to determine how many subjects in each group had a certain outcome.
Ex: follow groups of smokers and non smokers and observe lung cancer incidence.
cross-sectional studies
snapshot
categorize patients into different groups at a single point in time
case-control studies
start by identifying the number of subjects with or without a particular outcome, and then look backward to assess how many subjects in each group had exposure to a particular risk factor
ex: 100 patients with and without lung cancer are assessed for their past smoking tendencies.
ethnographic studies
used by sociologists to understand cultures by looking at the complete social environment
what criteria are used to determine the likelihood of causality between two variables?
Hill’s criteria
which one of Hill’s criteria is necessary for causality but not sufficient for it
temporality
Hill’s: temporality
the exposure must occur before the outcome
Hill’s: strength
greater variability of the independent variable leads to greater variability in the dependent variable
strength of association I believe
Hill’s: dose-response
as independent variable increases, dependent variable increases
Hill’s: consistency
relationship found in multiple settings
Hill’s: plausibility
there is a reasonable mechanism for the independent variable to impact the dependent variable
Hill’s: alternative explanations
eliminate other plausible explanations
Hill’s: experiment
can perform an experiment
Hill’s: specificity
the change in the outcome variable is only produced by an associated change in the independent variable
Hill’s: coherence
the new data and hypothesis are consistent with the current state of scientific knowledge.
____ is a result of flaws in the data collection phase of a study, while _____ is error during analysis
bias
confounding
selection bias
the subjects used for the study are not representative of the target population
ex: certain group of people is more likely to volunteer than another group of people.
detection bias
educated professionals using their knowledge in an inconsistent way
ex: obese individuals more likely to be screened for diabetes and hypertension, increasing the numbers of obese people with it diagnoses.
hawthorne effect/observation bias
the behavior of a study participant is altered simply because they recognize that they are being studied.
ex: individuals given weight loss drug are more likely to start working out which makes it look like the drug is having more of an effect than it actually is.
what is another name for observation bias
Hawthorne effect
what are the 4 ethical tenets of medicine?
beneficence, nonmaleficence, autonomy, justice
beneficence
the obligation to act in the patient’s best interest
nonmaleficence
the obligation to avoid treatments or interventions in which the potential for harm outweighs the potential benefit
autonomy
the responsibility to respect patients’ decisions and choices about their own healthcare.
justice
the responsibility to treat similar patients with similar care and to distribute healthcare resources fairly.
informed consent
a patient must be adequately counseled on the procedures, risks and benefits, and goals of a study to make a knowledgable decision about whether or not to participate in the study
Can a subject withdraw consent?
yes, at any time
what are considered vulnerable persons in research
children, pregnant women, prisoners,
respect for persons in research
honesty between researcher and participant
justice in research
selection of research topic and execution of research
beneficence in research
it must be our intent to cause a net positive change for both the study population and general population and we must do our best to minimize any harms.
equipoise
in studies comparing two potential treatment options, one cannot approach the research with the knowledge that one treatment is superior to the other.
coercive influence vs. monetary compensation
the line between a coercive influence and a compensatory influence is often debated. In general, compensatory influence is one that does not impact the decision to participate, while coercive influence is one in which the subject loses autonomy to make the decision to participate.
population
the complete group of every individual that satisfies the attributes of interest.
information that is calculated using every person in a population is called a ____
parameter
sample
any group taken from a population that does not include all individuals from the population.
information about a sample is called a _____
statistic
statistics can be used to _____ parameters with repeated sample collection
estimate
internal validity
support for causality
the extent to which you are sure the independent variable caused the dependent variable.
external validity
generalizability
the extent to which study results apply to the larger population
statistical significance
not the result of chance
clinical significance
a notable or worthwhile change in health status as a result of our intervention
statistical significance vs. clinical significance
just because there is mathematical statistical significance does not mean this will change patient outcomes.
why might small samples provide insufficient info about an entire population?
higher likelihood of selecting an outlier or by chance the data being skewed
a study without ______ may be one that resulted in chance and one without ______ will have no effect on patients
statistical significance
clinical significance
____ dictates which study questions are worth pursuing and which subjects to use.
justice
