Week 141 - Measurements in populations II

Question 1

What is chance?

Answer 1

The occurrence of an event based on probability

Question 2

What is selection bias?

Answer 2

The selection of controls that are not representative of the population

Question 3

What is information bias?

Answer 3

Recall bias

i. e. asking a person what they ate at a certain event
- people will recall information to a different accuracy

Question 4

What is a confounding variable?

Answer 4

A variable that can cause or be associated with the disease and is also linked the the exposure of interest

i. e. a study between alcohol intake and IHD
- those who drink alcohol are more likely to smoke, and smoking has an association with IHD

Question 5

What is residual confounding and how can this be dealth with?

Answer 5

When all confounding factors have been accounted for but there remain unknown confounders

Can be dealth with by randomisation

Question 6

What is standardisation ad what types are there?

Answer 6

A technique used to remove the effects of differences in confounders (i.e. age) when comparing two or more populations

Two types:

• Indirect
• Direct

Question 7

What is indirect standardisation?

Answer 7

Rate of a certain disease in a reference population is calculated then these raes are applied to the study population

If calculated rates < actual study rates => study population has a higher rate of disease