Monday - Reliability
13 important questions on Monday - Reliability
What to do against random errors?
- repeat measurements and take mean
- in case of questionnaires/exams: ask more questions
- more subjects in experiment
What are random and systematic errors?
Systematic: defect measurement equipment, misreading etc.
What to do against systematic errors?
- use gold standard to assess bias
- Higher grades + faster learning
- Never study anything twice
- 100% sure, 100% understanding
What is included in noise?
What is the repeatability coefficient?
- when two measurements are taken under identical conditions (close in time)
What is the reproducibility coefficient?
- when two measurements are measured under possibly different conditions (different weather, observers, instruments etc).
- no systematic differences
How are the residuals calculated?
--> Variance = σ^2 tot = σ^2 p + σ^2 e
σ tot = sqrt(variance)
What is a different name for the reliability coefficient?
Precision can be influeced by taking multiple measurements, the reliability when taking multiple measurements can be calculated with which equation?
h is the amount of measurements done
What is a bland-Altman plot?
Also calculate the differences di = yi - xi
Plot with x-axis is mean and y-axis
What is the con of a Bland-Altman plot?
What is Cohen's kappa?
How do you calculate Cohen's kappa?
Calculate the complete agreement, this are all counts on diagonal and divide this by the total observations.
Calculate the expected agreement = P11 + P22 + P33 etc. = (32/50)*(29/50 + (8/50)*9/50) + (12/50)/(10/50)
Then, k = (Po - Pe)/(1 - Pe)
The question on the page originate from the summary of the following study material:
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- Never study anything twice again
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