Stats and ethics

Question 1

What does the box whisker charts measure and what does the box mean

Answer 1

25th -75th centile
Median
Range and interquartile range

Question 2

Which average measure parametric and non parametric data

Answer 2

Parametric - mean

Non parametric - median

Question 3

What do the size of the boxes in a forest plot represent

Answer 3

Weight or power of the study

Question 4

P value definition

Answer 4

P value is probability that the observed difference could have occurred due to random chance

Question 5

Describe a type 1 alpha error and a type 2 beta error

Answer 5

Type 1 false positive - incorrectly rejecting the nul hypothesis, preg man

Type 2 false negative - incorrectly accepting the nul hypothesis - preg woman

Question 6

Define the power of a study

Answer 6

Ability of a study to find a statistically significant difference
depends on the actual difference between the two groups, p value and number of subjects

Question 7

What is ARR

Answer 7

Difference between the event rate in 2 groups

Question 8

What is the relative risk reduction.

Answer 8

ARR/ control event rate

Question 9

Number need to treat calculation.

Answer 9

100/ ARR %

Question 10

Define sensitivity

Answer 10

Ability of a test to correctly predict a positive outcome where one exists

Question 11

Define specificity

Answer 11

Ability of a test to correctly predict a negative outcome where one exists

Question 12

What is student t test used for

Answer 12

Continuous parametric data paired or unpaired

Question 13

Four rules of capacity

Answer 13

Patients are assumed to have capacity
All efforts to help patients participate in decisions
Different decisions do not make the decision wrong
Facilitate the communication of the decision

Question 14

What is required for consent to be valid

Answer 14

Voluntary
Informed
Patient with capacity

Question 15

What can be documented in an advanced directive

Answer 15

Dnar
Maximal intensity of care requested
Treatments deemed unacceptable
Statement on acceptable quality of life

Question 16

What is the standardised mortality ratio

Answer 16

Smr = observed mortality rate / expected mortality rate

Question 17

What is section 29

Answer 17

Section 29 of dpa permits to disclose information but does not require you. Need patient consent.

Question 18

When to disclose information to the police

Answer 18

Road traffic accident leading to the identification of the driver

Protect patient or prevent others from harm

Incidents involving terror

Serious communicable disease

Question 19

What form do the police have to complete to get blood sample

Answer 19

DP7

Question 20

How many consultants per patient and how many junior doctors

Answer 20

1 consultant for 8-15 patients

I junior for 8 patients

Question 21

Parametric statistical tests

Answer 21

T-test for 1, 2 and paired data

Continuous - Pearson’s

Question 22

Non parametric statistical test from 2 groups, paired data and continuous

Answer 22

2 groups- man and Whitney
Paired wilcoxon
Continuous- spearmans

Question 23

Categoric(binary) statistical test for 2 group, paired and continuous

Answer 23

2 groups- chi 2
Paired - mcnemar
Continuous- logistic regression.

Question 24

What is attrition bias

Answer 24

Failure to account for withdrawal from the study (loss to f/u)

Question 25

What is performance bias

Answer 25

Bias from the actions of the volunteers and researchers (blinding)

Question 26

Define standard deviation

Answer 26

Measure of the spread of scores in a set of data around the mean

Question 27

Define the standard error of the mean

Answer 27

Reflects the true population mean and equals the sd/ sq rt sample size