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Flashcards in biostatistique Deck (145)
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1

standard deviation normal distribution a 68%

SD a 1 from the mean

2

standard deviation normal distribution a 95%

SD a 2 from mean

3

standard deviation normal distribution a 99,7%

SD a 3 from the mean

4

example mean a 230 mg/dl pour le cholesterol and SD a 10,what's the value for cholesterol if observations are 95%

210-250

5

disease with increasing prevalence and stable incidence what happened(2)

any rx which prolongs life
good quality of care

6

Quid of PPV(2)

positive predictive value
pobability of having the disease if the result test is positive

7

quid of negative predictive value

probability of having the disease if the test is negative

8

quid of null hypothesis

no relationship between exposure and outcome

9

example of null hypothesis

CRP high and colon cancer ,no relationship

10

what to consider when evaluating the effectiveness of new trial drug

the natural history of the disease

11

example drug effectiveness and drug trial(2)

effectiveness of antiviral drug and flu
no exact conclusion can be drawn becausecommon cold is a self limited disease

12

in hazard ration interpretation what are the 2 key factors to consider(2)

control arm
rx arm

13

quid of hazard ratio <1

the event will occur in the control arm

14

quid of hazard ratio > 1

the event will occur in the rx arm

15

practice of hazard ratio

the chance for an event to occur during taking a drug for instance

16

interpretation of hazard ration close to one

no difference for an event to occur in the 2 groups rx arm and control arm

17

what information is critical to successfull randomization

baseline characteristics

18

what an ideal randomisation

process to minimize selection biais and achieves possibility of cofounding variables

19

a study is done using placebo and Rx,the assignment of the rx in teh two arm is done randomly using numbers generated by computer what randomization helps to do in ths case?

to eliminate confounder

20

what methods are used to eliminate cofounder during analytic stage of study

stratified analysis
modeling

21

what methods are used to eliminate cofounder during adesign stage of study(3)

matching
restriction
randomization

22

clue for randomization(2)

Rx group
Placebo group

23

when using randomization

during clinical trials

24

quid of restriction

when you limit your study to one group for example one sexe is considered

25

problem with restriction

you cannot generalize your finding in the population

26

when using matching

control studies

27

importance in using macthing(2)

when you want to study risk factor(
exposure and outcome

28

practice of macthing

you will take a group with a known risk factor and another one without it and compare

29

quid of false negative

the test is negative but you have the disease

30

consequence of raising the cut off value

false negative will increase