I am currently an A level student and completed the AS exams last year. I know how difficult it is to revise from the textbook so I have made concise notes on the first 4 sub topics of topic 1, including relevant diagrams from the textbook. I will make more if I gain interest! Good luck :)
1.2: Who is at risk of cardiovascular disease?
Probability and risk:
What do we mean by risk?
i) Risk= ‘the probability of occurrence of some unwanted event or outcome’
Different types of risk factor:
Risk factors= ‘things that increase the chance of a negative outcome’
Different factors that contribute to health risks: age; hereditary; physical
environment; social environment; lifestyle and behaviour choices
Identifying risk factors-correlation and causation
to determine risk factors for particular diseases, scientists look for correlations
between potential risk factors and the occurrence of the disease
correlation= between two variables when a change in one variable is accompanied by
a change in the other
Two variables= positively correlated when an increase in one is accompanied by an
increase in the other {vice-versa for negative with decrease in both}
Large amounts of data are needed to ensure the correlation is statistically significant
A correlation between two variables doesn’t mean that they are causally linked
Two variables are causally linked when a change in one is responsible for a change in
the other
Scientists use the logical gap between causation and correlation to carry out
experiments to see if altering one variable has a predicted effect
ii) To do this a null hypothesis is set up
iii) Assume that there will be no difference between an experimental group and a
control group and they then test this using statistical analysis
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