Stats and ethics Flashcards
What does the box whisker charts measure and what does the box mean
25th -75th centile
Median
Range and interquartile range
Which average measure parametric and non parametric data
Parametric - mean
Non parametric - median
What do the size of the boxes in a forest plot represent
Weight or power of the study
P value definition
P value is probability that the observed difference could have occurred due to random chance
Describe a type 1 alpha error and a type 2 beta error
Type 1 false positive - incorrectly rejecting the nul hypothesis, preg man
Type 2 false negative - incorrectly accepting the nul hypothesis - preg woman
Define the power of a study
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
What is ARR
Difference between the event rate in 2 groups
What is the relative risk reduction.
ARR/ control event rate
Number need to treat calculation.
100/ ARR %
Define sensitivity
Ability of a test to correctly predict a positive outcome where one exists
Define specificity
Ability of a test to correctly predict a negative outcome where one exists
What is student t test used for
Continuous parametric data paired or unpaired
Four rules of capacity
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
What is required for consent to be valid
Voluntary
Informed
Patient with capacity
What can be documented in an advanced directive
Dnar
Maximal intensity of care requested
Treatments deemed unacceptable
Statement on acceptable quality of life
What is the standardised mortality ratio
Smr = observed mortality rate / expected mortality rate
What is section 29
Section 29 of dpa permits to disclose information but does not require you. Need patient consent.
When to disclose information to the police
Road traffic accident leading to the identification of the driver
Protect patient or prevent others from harm
Incidents involving terror
Serious communicable disease
What form do the police have to complete to get blood sample
DP7
How many consultants per patient and how many junior doctors
1 consultant for 8-15 patients
I junior for 8 patients
Parametric statistical tests
T-test for 1, 2 and paired data
Continuous - Pearson’s
Non parametric statistical test from 2 groups, paired data and continuous
2 groups- man and Whitney
Paired wilcoxon
Continuous- spearmans
Categoric(binary) statistical test for 2 group, paired and continuous
2 groups- chi 2
Paired - mcnemar
Continuous- logistic regression.
What is attrition bias
Failure to account for withdrawal from the study (loss to f/u)
