week one Flashcards
Hypothesis
Stated as effect of independent variable on the dependent varible
Primary hypothesis
Test hypothesis for which an experiment is powered
Secondary hypothesis
Often times other effects of an IV of an IV are examined
But the effects is not necessary powered to state an effect statistically
Null hypothesis
Statistical concept which state there is not effect of IV on the DV
One sided hypothesis
You assume the DV will move in one direction
Two sided hypothesis
You do not know if DV will go up or down
Structural of hypothesis
-form the basis of all questions
-should be reflected in title of manuscript
-abstract
-posters
Grant application
They are the basis of Specific Aims in grant
IV
What the investigator control/manipulate to produce a change of DV
Should be only one depended factor
Does, choice,
DV
what the IV affects, what you measure
Frequency
Change HR
Ml of urine
Confounding variable
Unknown factors that disrupt or influence the effect of the IV on the DV
Random error
Inherent aspect of measurement which increase variability and reduces the ability to detect differences among the group
Why random person error is very. Difficult to control
As it an inherent aspect of measurements and pure and unknown
Confounding variable is control by
Randomized blocking with reduces the influence of confounding
But it will increasing variablity
Aim of experimental design is to
Isolate the effect of the IV on the DV
Type of control
Positive control Negative control Vehicle control Sham control Procedural control repeated measure
Positive control
Group added to a design where you know what the outcome will be and the outcome is expected to move in the direction of think the independent variable should move it
Positive CONROL used
To ensure that the experimental set up is working
By moving the experimental and positive control in the anticipated direction
So the design is more valid by IV is actually affecting the DV
- provide a comfort about the effects of the independent variable
- tell you the system is set up correctly and working enhancing your confidence in the negative results are truly negative
When. We can used positive. Control
Whenever you possible
Negative control
Is a group added to a design where you know the outcome, but unlike the positive control you known that the IV will not affect the group
Benefit of the negative control
Helps guard against epiphenomenon , it tells you that is something else influencing the
Do
Epiphenomenon
A result that accompanies another, but has no causal influence itself or was not caused by experimental paradigm
Vehicle control
This has everything you are administering except the level of the IV
Sham control
Associated with a surgical intervention where a mock surgery is performed , A form of a procedural control
Procedural control
Running the same procedure without the active intervention
Repeated measures
Use the subject as its own control or alternatively in a non-repeated measures design
-so it reduces the effects of intrasubject variability
The ability to generate good data the useable and interpretable is dependent upon
- good control over environment in which the study is performed
- how independent, or controlled, the outside effects of that environment are on the independent and dependent variables
Type of research
Hypothesis driven research -discovery research -clinical trail -Cohort study -Cross sectional study -case control studies Ethnographic research Explanatory research -historical research Quasi experiment
Hypothesis driven research
Specific hypothesis is laid out up front
Thes test prospectively
-used in clinical studies
Is show an association but not cause and effect
Prospective studies
Study where a hypothesis is formulated and then tested after the design has been laid out
Retrospective studies
Assess the effect of an IV on a DV after the fact i.e. After the IV affect on the DV has occurred
Discovery research
Formulates the basis for hypothesis driven research
Involves mining data sets or output to determine if a relationship will emerge so that a hypothesis can be formulated
-. Type genomic, proteomics and metabolic research l
Clinical trial
A study on patients that it’s always prospective and tests a very specific hypothesis generally about a drug or specific type of intervention
Clinical Trial
Is a specific type of design involving patients , it is an experiment, not just a study, in humans
Cohort study
Study of a group of subjects that share something in common and are assessed as they move forward in time , prospective study
Cross sectional study
Similar to a cohort study except that all the measures are taken at the same time (once)always retrospective studies
Case control
Start by disease and looks back
Ethnographic research
Study a human behavior in its natural contents , involving observation of behavior and physical setting
Explanatory research
Experimenter attempts to identify cause and effect
—cause and effect. Assumes that we identify the actual cause of something
- to identify cause and effect one generally runs multiple studies to isolate one factor that can be shown to cause the effect
Historical research
Systematic collection and evaluation of data related to past occurrences in order to describe causes , effects, and trends fo those events that may help explain present events and anticipate fur true events
Quasi experiment
Empirical study used to estimate the causal impact of an intervention on it is targe population
- share many similar with the traditional experimental design or randomized controlled trial , but lack the element of random assignment to treatment or control
- the investigator does not have control over the assignment of the IV as is true in regular experimental design
Quasi experimental designs typically allow the researcher to control
The assignment to the treatment condition but using some criterio other than random assignment
Prevention trial
Look for better way to prevent disease
Screening trials
Best way to detect certain disease
Quality of life trials supportive care trials
Explore ways to improve comfort and quality of life for individuals with a chronic disease
Compassionate use trial
Expanded access trials provide partially tested, unapproved therapeutics to a small number of patients who have no other realistic options
Usually case by case approved by FDA
