Ch. 4 Research Principles Flashcards

1
Q

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

A

Cross sectional study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

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

A

Case Control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

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

A

Case Control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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

A

Cohort Study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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

A

Cohort study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

subjects allocated to different interventions, placebo versus treatment group

A

RCT randomized control trial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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

A

RCT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

statistical test to compare means between two groups

A

student’s t-test or Wilcoxon rank sum test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

statistical test to compare means between 3 or more groups

A

ANOVA or Kruskal-Wallis test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

statistical test to compare two quantitative measurements from one source

A

paired t test or Wilcoxon signed rank test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

statistical test to determine degree of association between to quantitative variables

A

Pearson coefficient of correlation or Spearman rank order coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

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

A

Null hypothesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

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

A

P value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

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

A

type 1 error or alpha error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

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

A

type 2 error or beta error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

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

A

underpowered study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

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

A

Statistical power

18
Q

statistical power is usually set to what percentage

19
Q

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

20
Q

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

21
Q

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

22
Q

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

A

1-beta (equal to power)

23
Q

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

A

68%, 95%, 99.7%

24
Q

Difference between prevalence and incidence?

A

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
5 elements of informed consent
competence, disclosure, understanding, voluntariness, consent