Flashcards
Lecture 6
Flashcards do conjunto (24)
- 1What is the aim of descriptive studies?Descriptive studies is a study that describes things and so it will can for example:
Describe the characteristics of people with a disease (person, place, time)
Describe the lifestyle patterns in a population
Describe the attitudes to health care
Overall allowing us to see characteristics of a population at one point in time - 2What are descriptive studies often simply referred to as?Cross sectional studies and surveys
- 3What do we usually use for descriptive studies?We generally use a sample from the population of interest
- 4What does random sampling provide?Random sampling is where every individual that has been sampled via this method has a chance of being selected.
-This would reduce bias and/or systematic errors
-This would get a representation of the population
-There is usually a range of variables - 5What is random error? How do we reduce it?Random error is due to natural biological variability. It can be reduced by increasing the sample size (as fluctuation in the mean is reduced)
- 6What is systematic error?This error that is due to aspects of the study design/conduct of the study which systematically distorts the results. Usually arises when the sample is not a representative of the population.
This cannot be reduced by increasing the sample size. - 7What is the purpose of analytic studies?Analytic studies is to test hypotheses regarding
-causes of disease
-methods for prevention of disease
-the effects of treatments - 8What are the 2 main study designs for analytic studies?-Experimental studies
-Observational studies - 9Explain experimental studiesExperimental studies is where the researcher intervenes and records the result of their intervention.
You must control all other factors to isolate effects of intervention. Trying to get rid of other factors that can increase errors
This is the best way to study causation - 10What is the best way to study causation?Through experimental studies
- 11Describe observational studiesThis is where the investigator does not intervene but simply observes a naturally occurring process and then collects information.
The idea of an observational study is to get a result that is as close as possible to the information that would have been obtained if the experimental study could have been done - 12Is there random allocating of groups for experimental studies?Yes! As the researcher intervenes
- 13Is there random allocating of groups in observational studies?No! The researcher does not intervene. The people are categorised in different groups according to the person
- 14What sort of study is usually used in experimental studies?A randomised control trial
- 15What sort of study is usually use in observational studies?Cohort and case control studies
- 16What are the 2 important characteristics of a randomised control trial. Explain them1. Randomisation (random allocation) This means that every study unit has the same change of being in each group.
2. Control group. There must be this so that the effects of interventions can be isolated and it also allows us to see if there is any systematic difference - 17Why is there sometimes blinding in a randomised controlled trial?Blinding can be used to prevent bias and to get rid of any unconscious bias that researchers may have towards participants.
(Blinding/double blinding) - 18What are the advantages of doing a randomised control trial?This is the best way to test an hypothesis
If it is a good trial then differenced in outcome can be contributed to the intervention (causation) - 19What is a disadvantage of using a randomised control trial?It may not be eithical or feasible
- 20What is a cohort study and what are its characteristics?It is an observational study that is carried out to test hypotheses.
The characteristics of a cohort study:
-Participants are selected before the disease has developed
-Participants are followed over time to determine the development of the disease.
-Information is collected about exposures at baseline and during follow up. (following up to see results) - 21What are the advantages of a cohort study?It is good for examining common outcomes
It is also the closest observational study to randomised controlled data
it can also evaluate the exposure on multiple outcomes - 22What are the disadvantages of a cohort study?A long duration might be needed if the disease takes a long time to develop after exposed
If the disease is rare, then the number of participants need to be very large - 23Describe what a case control study is-This is an observational study that is generally carried out to test hypotheses.
The characteristics of this is that people are chosen on their disease status and that information is collected from people with and without the disease about exposures that occurred in the past. (Going back to see the history of the participants) (retrospective) - 24What is an advantage of a case control study?It is relatively quick.
The participants can be smaller as we dont need to consider the factor that the participants wont develop the disease. We are able to examine multiple exposures.
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- University Statistics FlashCards sobre Lecture 6, criado por arielhchen em 01-08-2015.
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