CAL 2 Flashcards
How do you calculate an odds ratio
number of case x number of control exposed / number of controls exposed x number of case
What odds ratio is associated with no effect
1:1 or 0
if a confidence interval for an odds ratio contained 1, then the associated P value is greater than 0.05
if a confidence interval for an odds ratio does not contain one then the associated P value is less than 0.05
what is a chi squared test
- this is when the P value is calculated by comparing the observed numbers in the table to those expected if there was no association between the two groups and stimulus
How do you work out the risk of dying
number of deaths/ number of patients in group
how do you work out the risk of dying per 100
risk of dying x 100
How do you work out the relative risk of dying
risk of dying per 100 in experiment group/ risk of dying per 100 in placebo group
How do you work out percentage increase
original - new/new
how do you work out percentage decrease
original - new/ original
what does the P value have to be in order to be significant
P value has to be less than 0.05 to be significant
if there is a 1 present
it is not significantly significant
