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NAPLEX Review > Biostatistics > Flashcards

Biostatistics Flashcards

1
Q

What is continuous data?

A

Data with a logical order
Values that continuously increase or decrease – have theoretically infinite options
Examples: age, height, weight, time, BP, temperature

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2
Q

What are types of discrete (categorical) data?

A

Nominal and ordinal

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3
Q

What is nominal data?

A

Categories – order does not matter

Examples: gender, ethnicity, marital status, mortality

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4
Q

What is ordinal data?

A 
Categories are ranked in logical order but difference between categories is not equal
Examples: NYHA functional class I-IV; 0-10 pain scale
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5
Q

What is the spread of data?

A

How much it varies

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6
Q

What is the range of data?

A

Difference between highest and lowest value

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7
Q

What is the standard deviation (SD) of data?

A

Indicates how spread out the data is, and to what degree the data is dispersed away from the mean

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8
Q

What is Gaussian distribution?

A

Normally shaped “bell curve”

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9
Q

On a bell curve, ___% of values fall into one standard deviation of the mean, ___% fall into 2 standard deviations of the mean

A

68%

95%

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10
Q

Independent vs dependent variables

A

Independent: Changed by researcher
Dependent: affected by independent variables

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11
Q

What does the null hypothesis state?

A

No statistically significant difference between groups

***Researcher tries to reject this

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12
Q

What does the alternative hypothesis state?

A

There is a statistically significant difference between groups
***Researcher tries to prove this

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13
Q

What is the alpha value?

A

Threshold for rejecting null hypothesis
“error margin”
Usually 0.05 or 5%

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14
Q

If p-value is ___ alpha, null is rejected and result (is/is not) statistically significant

A

Less than alpha

is

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15
Q

What is the confidence interval? How is it calculated?

A

Provides same info about significance as p-value, plus precision of the result
1-alpha = CI

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16
Q

If a confidence interval (CI) includes ____ it is not statistically significant

A

0: when comparing difference data
1: when comparing ratio data

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17
Q

Which indicates high precision, narrow or wide CI?

A

Narrow

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18
Q

What does a 95% confidence interval indicate?

A

You are 95% sure that the true value falls between the range given

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19
Q

Type 1 error = false _____

Type 2 error = false _____

A

Type 1: false positive

Type 2: false negatives

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20
Q

What does the study power indicate?

A

The probability that a test will reject the null hypothesis correctly
Power to avoid type II error

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21
Q

If beta is 0.2, what is the study power?

A

80%

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22
Q

What is relative risk?

A

Risk in the exposed group (treatment) divided by risk in the control group

23
Q

Risk formula

A

Total number of subjects in a group

24
Q

Relative risk formula

A

Risk in control group

25
Q

What does relative risk of 1, >1, or <1 mean?

A 
1 = no difference in risk between group
>1 = greater risk in treatment group
<1 = less risk in treatment group
26
Q

Relative risk reduction calculation

A

5 risk control group

OR

1-RR

27
Q

What is relative risk reduction?

A

Indicates how much risk is reduced in treatment group

28
Q

Absolute risk reduction calculation

A

(% risk in control group) – (% risk in treatment group)

29
Q

What does an absolute risk reduction (ARR) of 12% mean?

A

12 out of every 100 patients benefit from treatment

30
Q

Number needed to treat calculation

A

1/(risk in control group – risk in treatment group)

OR

1/ARR

31
Q

Which way do you round number needed to treat (NNT)? Number needed to harm (NNH)?

A

NNT – round up

NNH – round down

32
Q

What is odds ratio (OR)?

A

Used to assess the odds of an outcome occurring with an exposure compared to odds of the outcome occurring without the exposure

33
Q

What is hazard ratio?

A

Rate at which an unfavorable event occurs within a short period of time

34
Q

Hazard ratio (HR) calculation

A

Hazard rate in control group

35
Q

What is a composite endpoint?

A

Combined endpoints into one measurement

36
Q

What test should be used with numerical/continuous data with one group

A

One-sample t-test

37
Q

What test should be used with numerical/continuous data with two groups (e.g treatment and control)

A

Independence/unpaired student t-test

38
Q

What test should be used with numerical/continuous data with three or more groups

A

ANOVA

39
Q

What test should be used with discrete/categorical data with two groups

A

Chi-squared test or Fisher’s exact test

40
Q

What is correlation

A

Statistically technique that is used to determine if one variable changes or is related to another variable

41
Q

What is regression used to describe?

A

The relationship between a dependent variable and one or more independent variables or ho much the value of the dependent variable changes when the independent variables changes

42
Q

What does sensitivity/specific indicate?

A

Sensitivity – true positive; positive in patients with the condition
Specificity – true negative; negative in patients without the condition

43
Q

What is intention-to-treat analysis?

A

Includes data for all patients originally allocated to each treatment group even if they did not complete the trial according to study protocol

44
Q

What is per-protocol analysis?

A

Includes data for all patients who completed the study according to protocol

45
Q

What are equivalence and noninferiority trial designs?

A

Equivalence – demonstrates new treatment has ~equal effect the old treatment
Non-inferiority – new treatment is no worse than current standard based on predefined non-inferiority margin

46
Q

What do forest plots provide?

A

Cis for difference data or ratio data

47
Q

Characteristics of case-control studies

A

Retrospective

Compare cases to controls

48
Q

Characteristics of cohort studies

Limitations

A

Retrospective or prospective
Compare patients with an exposure to those without an exposure
Limitations: can be influenced by confounders

49
Q

Characteristics of randomized controlled trials

A

Prospective

Compare patients who were randomly assigned to groups

50
Q

Characteristics of meta-analyses

A

Analyzes the results of multiple studies

51
Q

Characteristics of systematic review article

A

Summary of the clinical literature that focusses on a specific topic or question

52
Q

Characteristics of case report or case series

A

Describes adverse event or condition in a single patient (report) or a few patients (series)

53
Q

What does pharmacoeconomics do?

A

Identifies, measures, and compares the costs and consequences of pharmaceutical products and services

54
Q

What are some indirect and intangible medical costs?

A

Indirect: lost work time, low work productivity, morbidity, mortality
Intangible: pain, suffering, anxiety, fatigue

NAPLEX Review (79 decks)

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