Research

Question 1

Sensitivity, specificity, PPV, NPV

Answer 1

Sensitivity: Measure of true positives
Specificity: Measure of true negatives
PPV: Proportion of positives that are true positives
NPV: Proportion of negatives that are true negatives

See fig in album

HINT: PPV - all positives in the formula

Question 2

Kaplan Meir curve

Answer 2

Survival analysis over time plotted over y axis where x axis represents time using multiple predictors.

Parametric test.

Non-parametric variant - Cox regression which can also use non-normal data.

Question 3

1 variable 2 categories between subjects test

Answer 3

Parametric- unpaired t test
Non parametric- Mann-Whitney U test

Question 4

1 variable 2 categories within subjects test

Answer 4

Parametric: paired t test
Non parametric: Wilcoxon signed rank test

Question 5

1 variable >categories test

Answer 5

Parametric: ANOVA - difference between means
Non parametric: Kruskal Wallis

Question 6

1 variable continuous data test

Answer 6

Parametric: Pearson’s r test
Non parametric: Spearman’s p test

Question 7

Levels of evidence

Answer 7

1. High quality RCT & meta analysis
2. Lesser quality RCT, prospective comparative study
3. Retrospective comparative study & Case control study
4. Case series, case reports
5. Expert opinion

Question 8

Case control study

Answer 8

In a case-control study, researchers identify 2 groups: cases and controls.

Cases are people who already have an outcome (such as breast cancer).
Controls are people who do not have the outcome.
The researchers compare the 2 groups to see if any exposure (such as alcohol use) was more common in the history of one group compared to the other.

Randomized controlled trials

In randomized controlled trials (randomized clinical trials), researchers divide people into groups to compare different treatments or other interventions.

These studies are called randomized controlled trials because people are randomly assigned (as if by coin toss) to a certain treatment or behavior.