Stats Flashcards

1
Q

Why are stats important?

A
  • some forms of statistics have predictive utility
  • future risk
  • focused on application
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2
Q

SD:

A

a measure of variability within the cohort being assessed

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3
Q

2 x SD will capture ____% of the _____ (_____ ) of data.

A
  • ~95%

- range (distribution)

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4
Q

Standard error (of the mean):

A
  • determining whether the mean is applicable for the entire population
  • accuracy of the mean (generalizability to similar cohorts or population)
  • how much do we trust this number?
  • if you use the entire population, would you get a similar number?
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5
Q

Standard error is dependent on…

A
  • the SD

- the sample size

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6
Q

OR & RR used to represent the effect of an _____ on a particular outcome.

A

intervention

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7
Q

Odds ratios (OR):

A

what are the odds of something happening given a particular exposure or intervention compared to control?

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8
Q

OR =

A

odds of an outcome in the exposed group / odds of an outcome in the control group

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9
Q

(Relative) risk ratio:

A

identifies the probability of an outcome given an exposure or intervention (more intuitive)

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10
Q

RR =

A

probability of an outcome in the exposed group compared to the control group

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11
Q

OR and RR attempt to describe…

A

the same effect

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12
Q

OR and RR express the influence of an ____ or _____ in separate ways (but they are _____).

A
  • exposure
  • treatment
  • related
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13
Q

OR and RR _____ the occurrence of an ____ (due to ____) in reference to a ____ group.

A
  • normalize
  • outcome
  • exposure
  • control
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14
Q

OR and RR are commonly used in ____.

A

medicine

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15
Q

Validity:

A
  • accuracy
  • correctness
  • does a test, instrument, questionnaire, etc. measure what it is supposed to measure?
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16
Q

Reliability:

A
  • precision

- repeatability

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17
Q

Types of validity:

A
  • logical (face) validity
  • content validity
  • criterion validity
  • construct validity
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18
Q

Logical or face validity can be claimed when…

A

the measure appears to obviously assess the target variable or performance

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19
Q

Give an example of logical (face) validity:

A
  • balance test of standing on one foot

- it obviously is measuring balance

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20
Q

Logical (face validity):

A
  • weakest form of validity
  • may be difficult to quantify
  • no statistical verification
  • established by expert opinion or judges
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21
Q

Content validity is similar to _____ validity and usually applies to ____ ____ or _____ that attempt to measure the desired ____ or a defined _____ of ____.

A
  • logical
  • written tests or questionnaires
  • parameter
  • domain of content
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22
Q

In content validity, often a table of ____ and/or ____ are developed to act as a _____.

A
  • specifications
  • diagrams
  • blueprint
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23
Q

Content validity is established through ____ ____ or _____ _____.

A
  • published literature

- curriculum content

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24
Q

In content validity, often no _____ ____ is usually required.

A

statistical verification

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25
Give an example of content validity:
visual rating scale for body composition
26
Criterion validity:
the extent to which the results of a standard test can be compared to or used to predict a practical outcome
27
Criterion validity can be claimed when...
- a test measure provides an outcome similar to a criterion (standard) or previously validated test measure - when the measure taken successfully predicts the criterion measure or gold standard - when the measures permit inferences to be made about an underlying trait
28
Give an example of criterion validity:
- is a 2000m simulated rowing race on a rowing machine a valid measure of an actual on-water 2000m rowing race? - predicting body fat from skinfolds
29
With construct validity, the variable of interest is...
multi-factorial/multi-dimensional
30
Construct validity requires more _____ statistical procedures such as...
- complex - factor analysis - multiple regression - ANOVA/multivariate ANOVA
31
Reliability refers to the _____ or _____ of a measurement.
- consistency | - repeatability
32
5 factors influencing validity/reliability:
- biological variability - technical variability - testing variability - environmental variability - unknown factors
33
Biological variability:
- the inherent physiological and psychological fluctuations of the individual - circadian rhythms, mood etc.
34
Technical variability:
precision and accuracy of the instruments
35
Testing variability:
instructions and manner of administering the test
36
Environmental variability:
- temperature | - humidity
37
Inter-rater reliability:
comparison of same measure between 2 (or more) testers
38
Intra-rater reliability:
comparison of 2 (or more) measures made by the same tester (tests the measure-er)
39
Test-retest reliability:
- repeated testing on 2 or more occasions | - used to test the reliability of the technique (repeatability)
40
6 keys to repeatability:
- same experimental tools - same observer - same measuring instrument, used under the same conditions - same location - repetition over a short period of time - same objectives
41
Intra class correlation needs _____ measures for x and y (______ data).
- same - interchangeable - ex. HR 1 and HR 2
42
ICC is...
- intra class correlation | - the repeatability of a measure
43
How to interpret ICC:
- less than 0.40 = poor - 0.40 - 0.59 = fair - 0.60 - 0.74 = good - 0.75 - 1.00 = excellent
44
3 ways to assess validity/reliability:
- correlation - regression - bland-altman
45
2 factors to consider for correlation:
- there should be physiological basis fundamentally linking the variables of interest - correlation does not mean causation
46
Why can HR be used to correlate oxygen consumption?
- fick equation | - HR is in it, fundamentally related
47
_____ and ______ are often presented at the same time.
- correlation | - regression
48
VO2 max =
CO x a-v O2 diff.
49
CO =
HR x SV
50
Although a correlation describes the ____ of the relationship between 2 variables, it does not necessarily describe _____ of the relationship.
- strength | - pattern
51
Regression describes...
the numerical relationship between 2 variables
52
The simplest regression can be...
the linear line of best fit
53
Multiple linear regression:
multiple factors may also be known to be co-related, influencing the relationship of interest
54
Example of multiple linear regression:
Ebbeling submaximal treadmill test
55
How can you assess how well 1 metric compares to the "gold standard"?
bland-altman
56
Example of bland-altman test:
comparing PA questionnaire and accelerometer
57
X axis of bland-altman:
average of the 2 values
58
Y axis of bland-altman:
difference of the 2 values
59
Average difference of the bland-altman tells you ...
if it on average overestimates or underestimates gold standard
60
Why do you need a large range when using bland-altman?
so that it is applicable to sedentary and active individuals
61
SD is how ____ the range is...
- big - how tight our relationship is around offset - want to minimize the 2 SDs
62
In the bland-altman, regression line (aka ...) is not a _____ but you can get _____ relationship.
- line of best fit - correlation (no r value) - y = mx + b
63
A mean offset of - 2.4 in the bland-altman means...
in order to estimate our gold standard, we have to add 2.4
64
In bland-altman, a big range of SD is ______.
unacceptable
65
Line of best fit in bland-altman:
across the entire range of individuals we are working with, sometimes we are underestimating our gold standard, while other times we are overestimating our gold standard
66
Ideal line of best fit for bland-altman:
- you would have no difference - you have same difference across entire range - you have line of best fit that is flat - your SD is narrow
67
Where do our guidelines come from?
meta-analysis
68
What is the condition for being used in a meta-analysis?
all need to be measuring the same thing
69
Meta-analysis:
- strict, defined process for conducting analysis - pool data to provide a larger sample size - the basis for many clinical practice guidelines
70
In meta-analysis, 0 means...
inconclusive
71
Meta-analysis is a highly regarding technique for interpreting _____/ ____ in data.
- variability | - controversy
72
Meta-analysis is used to determine ____ of outcomes across studies.
validity