Epidemiology 2a Flashcards
What can vary from one individual to the other?
Height (cm)
Weight (cm)
Waist (cm)
Hands & Feet (cm)
Skin -> no unit
Age (years, seconds, etc)
IQ -> no unit
Eyesight
etc…
This is known as anthropometry.
What is anthropometry?
The things which vary between individuals.
What can variables be?
Variables can be:
- Continuous
- Discrete
- Ordinal
- Nominal
Give an example of a continuous variable?
- Height, weight, waist circumference.
Give an example of discrete variable.
- 1 child, 2 children, 3 children
Give an example of ordinal variable.
- Bronze, Silver, Gold
- XS,S,M,L,XL
Give an example of nominal variable.
- Colours
- Sex
What is a median?
The remaining value, which is in the middle position when numbers are ordered.
What variables are classed as category-like data?
Nominal, Ordinal, Discrete (aka scale).
Define nominal variable.
Simple categories like yellow, green, and blue, or male and female.
Define ordinal variable.
Categories that can be ranked such as bronze, silver, and gold medals or small, medium and large size.
Define Discrete variable (aka scale)?
Discrete counts like numbers of coins in a pile or eggs in a nest.
Define continuous variable?
Measures like length of a finger measured with a ruler.
What variables are classed as continuous data?
Continuous variables
Whats bad about using a bar chart for means
the loss of detail as bar charts can oversimplify, leaving out important information such as variance, distribution, outliers, and trends, and numbers of individuals in a particular category.
What is used to measure standard deviation?
Standard deviation and Standard error of the mean
What is SD?
SD: Standard Deviation
What is SEM?
SEM: Standard Error of the Mean
What is the difference between standard deviation (SD) and standard error of the mean (SEM)?
SD = human participants (by convention)
SEM = non human studies (by convention)
Describe the study done on the prevalence of mental health disorders in French prisons for men.
Random sampling of prisoners :
From 20 prisons in metropolitan France
Until 800 prisoners have been enrolled
Acceptance rate for inclusion : 57%
Therefore, 1402 prisoners were contacted
Enrolment : Sept 2003 - Jul 200
Final sample = 799 prisoners
Generating 799 mental health interviews
Why is randomness so important?
- minimize bias and ensure that the results are representative of the population being studied.
- researchers can ensure that their sample is diverse and not skewed towards any particular group or outcome.
- increases the validity and reliability of the study’s findings
