Statistics

Question 1

What is the Absolute Risk?

Answer 1

The chance of something happening within a group

Question 2

What is the equation for Absolute risk?

Answer 2

ABSOLUTE RISK = (EVENTS/NUMBER OF PARTICIPANTS) x 100

Question 3

What is an example of absolute risk?

Answer 3

20 out of 100 people getting a new drug had a heart attack
The Absolute Risk of heart attack = (20/100)x100 = 20%

Question 4

What is Absolute Risk Reduction?

Answer 4

The difference between the chances of something happening in two different groups

Question 5

What is the equation for the Absolute Risk Reduction?

Answer 5

ABSOLUTE RISK REDUCTION = OLD PERCENTAGE – NEW PERCENTAGE

Question 6

What is an example of the Absolute Risk Reduction?

Answer 6

EG: 20% of people getting a new drug had a heart attack
50% of people getting the old drug had a heart attack
The Absolute Risk Reduction (ARR) is 50-20=30%

Question 7

What is the Relative Risk?

Answer 7

The chance of something happening with the new drug as a percentage of the old drug

Question 8

What is the equation for Relative risk?

Answer 8

RELATIVE RISK = (NEW PERCENTAGE/OLD PERCENTAGE)x100

Question 9

What is an example of Relative risk?

Answer 9

EG: 20% of people getting a new drug had a heart attack
50% of people getting the old drug had a heart attack

Question 10

What is the Relative Risk Reduction?

Answer 10

The percentage reduction in chance of an event from the old treatment

Question 11

What is the equation for relative risk reduction?

Answer 11

RELATIVE RISK REDUCTION = 100 – RELATIVE RISK

Question 12

What is an example of Relative Risk Reduction?

Answer 12

EG: 20% of people getting a new drug had a heart attack
50% of people getting the old drug had a heart attack
100 – 40 = 60%

Question 13

What is Number needed to treat?

Answer 13

How many patients you need to treat with the new drug to reduce 1 event occurring

Question 14

What is the equation for Number needed to treat?

Answer 14

NUMBER NEEDED TO TREAT = 100/ABSOLUTE RISK REDUCTION

Question 15

What is an example of number needed to treat?

Answer 15

EG: 20% of people getting a new drug had a heart attack
50% of people getting the old drug had a heart attack
100/30 = 3.333

Question 16

What is Specificity?

Answer 16

What is the chance of a negative test if you only tested healthy people

Question 17

What are the 2 points of specificity?

Answer 17

True negative
False positive

Question 18

What does true negative mean?

Answer 18

Does not have disease + tests negative

Question 19

What does fale positive mean?

Answer 19

Does not have disease + tests positive

Question 20

What is the equation for specificity?

Answer 20

SPECIFICITY = TRUE NEGATIVE/(TRUE NEGATIVE + FALSE POSITIVE

Question 21

What is an example if Specificity?

Answer 21

EG: 100 healthy people are tested for TB and 10 people test positive
90/(90+10) = 90

Question 22

What is Sensitivity?

Answer 22

What is the chance of an affected person testing positive

Question 23

What are the 2 points of sensitivity?

Answer 23

True positive
False negative

Question 24

What is True positive?

Answer 24

Has disease + tests positive

Question 25

What is false negative?

Answer 25

Has disease + tests negative

Question 26

What is the equation for Sensitivity?

Answer 26

SENSITIVITY = TRUE POSITIVE/(TRUE POSITIVE + FALSE NEGATIVE)

Question 27

What is an example of sensitivity?

Answer 27

EG: 100 people with TB are tested and 95 test positive 95/(95+5) = 95%

Question 28

What does Positive predictive value mean?

Answer 28

If a test is positive, what is the chance the person has the disease

Question 29

What is the equationf for positive predictive value?

Answer 29

POSITIVE PREDICTIVE VALUE = TRUE POSITIVE/(TRUE POSITIVE + FALSE POSITIVE

Question 30

What is an example of positive predictive value?

Answer 30

EG: 100 people with TB and 100 people without TB take a test 95 people with TB test positive 10 people without TB test positive Positive predictive value = 95/(95 + 10) = 90.5%

Question 31

What does negative predictive value mean?

Answer 31

If a person tests negative, what is the chance they do not have the disease

Question 32

What is the equation for negative predictive value?

Answer 32

NEGATIVE PREDICTIVE VALUE = TRUE NEGATIVE/(TRUE NEGATIVE + FALSE NEGATIVE)

Question 33

What is an example of negative predictive value?

Answer 33

EG: 100 people with TB and 100 people without TB take a test 5 people with TB tested negative 90 people without TB tested negative NEGATIVE PREDICTIVE VALUE = 90/(90 + 5) = 95%

Question 34

What does Odds Ratio mean?

Answer 34

The odds of something happening with a risk factor/treatment compared to the odds of something happening without a risk factor/treatment

Question 35

What does an Odds Ratio of more than 1 suggest?

Answer 35

Then the risk factor/drug made it more likely

Question 36

What does an Odds Ratio of less than 1 suggest?

Answer 36

The risk factor/treatment made it less likely

Question 37

What does an Odds Ratio of 1 suggest?

Answer 37

The risk factor/treatment had no effect

Question 38

When does Odds ration tend to be used?

Answer 38

Most often used in case control studies

Question 39

What is the use of a funnel plot?

Answer 39

A way to look for publication bias

Question 40

What does a funnel plot involve?

Answer 40

Compares the size of the study and what conclusion the study found

Question 41

What does a symmetrical funnel plot suggest?

Answer 41

Symmetrical plot = low risk

Question 42

What does an asymmetrical funnel plot suggest?

Answer 42

Asymmetrical plot = high risk