Week 5 Flashcards
What ratio is used for analysing Cohort Studies?
Relative Ratio
What does the Relative (or Risk) Ratio calculate?
The chance of developing a disease with expose of the chance of developing a disease without exposure
What is the rule for the Relative Risk Ratio?
- CIe/ Clo
- (a/(a+b))/(c/(c+d)) = (a(c+d))/(c(a+b))
(when using a 2 by 2 table)
What ratio is used for analysing Case- Control Studies (why is this ratio rather than the other)?
Odd’s ratio
The participants in the study already have the disease and the chance of developing the disease is not applicable.
What is the rule used to calculate the Odds Ratio?
- ad/bc
What does the Odds Ratio calculate?
The odds of exposure with a disease over the odds of exposure without the disease
The chance of a disease with exposure is __ times more likely then the chance of a control with exposure
What is the absolute value the same as?
The Cumulative Incidence
Explain Absolute Risk Reduction. What does it denote?
Clo-Cle
Must be noted with time
Applicable when a drug or inhibitor is used
Details: The number of people less getting the disease with exposure
Explain Relative Risk Reduction.
Decrease in the number of people with the disease (however, it is dependent on the sample size
Percentage value
Must always be shown with ARR
What is the NNTT?
The number needed to be treated to save one person from developing a disease
1/ ARR
What does the p-value show?
- The p-value is the likely the results collected occurred due to chance
- If p <0.05= Statistically significant and the null hypothesis is rejected
- If p>0.05= The results are not statistically significant and the null hypothesis is accepted
- Must be displayed with the 95% CI
What does the 95% CI show?
- A range of values
- If 100 studies were conducted the value for 95 well be within this range
- Can reveal is results are statistically significant without the p-value
What does it mean if the 95% CI= 1?
Not Statistically Significant
Null hypothesis is accepted as the RR or OR is equal to 1 (therefore, the chance of the study factor and the outcome are equal)
