Flashcards in Ch. 4 Research Principles Deck (40):

1

## Data regarding presence or absence of exposure and disease are collected at the same time

### Cross sectional study

2

## Compares subjects with a condition to those without and examines frequency of a risk factor in each group

### Case Control

3

## study that is useful in studying infrequent events and calculated odds ratio

### Case Control

4

## study that is the gold standard in observational epidemiology and calculate relative risk

### Cohort Study

5

## longitudinal study comparing a defined group of people who share a common experience within a defined period before developing outcome of interest

### Cohort study

6

## subjects allocated to different interventions, placebo versus treatment group

### RCT randomized control trial

7

## study that can be used to test preventive interventions and determine absolute risk reduction

### RCT

8

## statistical test to compare means between two groups

### student's t-test or Wilcoxon rank sum test

9

## statistical test to compare means between 3 or more groups

### ANOVA or Kruskal-Wallis test

10

## statistical test to compare two quantitative measurements from one source

### paired t test or Wilcoxon signed rank test

11

## statistical test to determine degree of association between to quantitative variables

### Pearson coefficient of correlation or Spearman rank order coefficient

12

## Hypothesis that there is no effect or no difference is called?

### Null hypothesis

13

## the probability that if the null hypothesis were true, we would observe a result as extreme than one observed in these study

### P value

14

## error that occurs when the null hypothesis is falsely rejected and we accept that a difference exists when it truly does not

### type 1 error or alpha error

15

## error that occurs when the null hypothesis is not rejected when a true difference exists

### type 2 error or beta error

16

## most common reason for a type 2 or beta error (not rejecting the null hypothesis)

### underpowered study

17

## ability of a test to detect a true difference in a data set or the probability of avoiding a type II error

### Statistical power

18

## statistical power is usually set to what percentage

### 80 to 90%

19

## if the null hypothesis is true and you accept the null hypothesis, what is the probability?

### 1 - alpha

20

## if the null hypothesis is true and you reject the null hypothesis, what is the probability?

### alpha

21

## if the null hypothesis is false and you accept the null hypothesis, what is the probability?

### beta

22

## if the null hypothesis is false and you reject the null hypothesis, what is the probability?

### 1-beta (equal to power)

23

## what percentage of observations fall within 1 SD, 2 SD, 3 SD of the bell shaped curve?

### 68%, 95%, 99.7%

24

## Difference between prevalence and incidence?

### prevalence is percentage of patients with disease at a given time, and incidence is measure of individuals that develops disease during a specified period

25

## Probability that a test will be positive for disease if the person has the disease

### sensitivity = TP / (FN + TP)

26

## Probability that a test will be negative if person does not have the disease

### specificity = TN / (FP + TN)

27

## a negative result for a highly sensitive tests can...?

### rule out disease

28

## a positive result for a highly specific tests can...?

### rule in disease

29

## the proportion of positive tests that are true positive

### PPV = TP / (TP+FP)

30

## the proportion of negative tests that are true negative

### NPV = TN / (TN + FN)

31

## PPV and NPV are affected by?

### prevalence

32

## How will PPV and NPV be affected by prevalence?

### high prevalence increases PPV, low prevalence increases NPV

33

## equation for absolute risk (AR)

###
ARC = # of events in control group / # of people in control group

ART = # of events in treatment group / # of events in treatment group

34

## equation for absolute risk reduction (ARR)

### ARR = ARC - ART

35

## equation for relative risk

### RR = ART / ARC

36

## equation for relative risk reduction

### RRR = (ARC - ART) / ARC = 1 - RR

37

## equation for number needed to treat

### NNT = 1/ARR

38

## equation for odds ratio OR

### OR = (TP x TN) / (FP x FN)

39

## three core principles in the Belmont Report

### respect for persons, beneficence, justice

40