EPIDEMIOLOGY EQUATIONS

Question 1

when RR>1, what does this mean?

Answer 1

risk of developing HRE is higher than the control group

Question 2

when RR=1, what does this mean?

Answer 2

risk of developing HRE is the same as the control group

Question 3

when RR<1, what does this mean?

Answer 3

risk of developing HRE is less than the control group

Question 4

when what is the equation for relative risk?

Answer 4

risk of HRE in treatment group/risk of HRE in control group

Question 5

when OR>1, what does this mean?

Answer 5

outcome of control is better than that of intervention

Question 6

when OR=1, what does this mean?

Answer 6

outcome of intervention is same as that of control

Question 7

when OR<1, what does this mean?

Answer 7

outcome of intervention is better than that of control

Question 8

when what is the equation for odds ratio?

Answer 8

odds of HRE in treatment group/odds of HRE in the control group

Question 9

when HR=0.5, what does this mean?

Answer 9

at any given time, half as many individuals in the intervention group are experiencing an event compared to the control group

Question 10

when HR=1, what does this mean?

Answer 10

at any given time, the same number of individuals in the intervention group are experiencing an event as in the control group

Question 11

when HR=2, what does this mean?

Answer 11

at any given time, twice the number of individuals in the intervention group are experiencing an even compared to the control group

Question 12

when LR=0-1, what does this mean?

Answer 12

decreased evidence for HRE

Question 13

when LR>1, what does this mean?

Answer 13

increased evidence for HRE

Question 14

what is the equation for likelihood ratio?

Answer 14

probability a person with HRE has a specified test result/probability a person without HRE has a specific test result

Question 15

when LR+>10, what does this mean?

Answer 15

test result has large effect on increasing probability of HRE

Question 16

when LR+=5-10, what does this mean?

Answer 16

test result has moderate effect on increasing probability of HRE

Question 17

when LR+<5, what does this mean?

Answer 17

test result has small effect on increasing probability of HRE

Question 18

Positive likelihood ratio (LR+) equation?

Answer 18

LR+=sensitivity/(1-specificity)

Question 19

when LR-<0.1, what does this mean?

Answer 19

test result has large effect on decreasing probability of HRE

Question 20

when LR-=0.5-0.1, what does this mean?

Answer 20

test result has moderate effect on decreasing probability of HRE

Question 21

when LR->0.5, what does this mean?

Answer 21

test result has small effect on decreasing probability of HRE

Question 22

Negative likelihood ratio (LR-) equation?

Answer 22

LR-=(1-sensitivity)/specificity

Question 23

relative risk equation?

Answer 23

RR=(A/(A+B))/(C/(C+D))

Question 24

odds ratio equation?

Answer 24

OR=(AxD)/(BxC)

Question 25

sensitivity equation?

Answer 25

sensitivity=A/(A+C)

Question 26

specificity equation?

Answer 26

specificity=D/(B+D)

Question 27

postive predictive value?

Answer 27

PPV=A/(A+B)

Question 28

negative predictive value?

Answer 28

NPV=D/(C+D)

Question 29

calculating numbers to treat experimental event rate equation? control event rate equation? absolute risk reduction equation equation? NNT equation?

Answer 29

A/A+B C/C+D CER-EER 1/ARR

Question 30

calculating numbers needed to harm experimental event rate equation? control event rate equation? absolute risk reduction equation equation? NNT equation?

Answer 30

A/A+B C/C+D CER-EER 1/ARI ARI=absolute difference between CER and EER