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25 Cards in this Set
- Front
- Back
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Nominal
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- numerical scale indicate a classification
- inclusion in one category is not better/worse, larger/smaller, etc. than another - no proportionality |
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Nominal Examples
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- male/female
- number on athlete's uniform - 1=OA, 2=RA, 3=Normal - Yes/No - Agree/Disagree |
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Ordinal
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- order or rank
- comparison of better than or greater than can be used - no proportionality |
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Ordinal Examples
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- MMT
- Pain Scale - Finish in a race - Likert scale (faculty evals) |
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Interval
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- equal intervals between numbers, but not related to absolute zero
- all "made up" scales - some proportionality |
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Interval Examples
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- IQ
- Fahrenheit - Centigrade - Calendar Years - Gymnastics score |
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Ratio
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- highest level of measurement
- contains all characteristics of other three scales - absolute zero |
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Ratio Examples
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- ROM
- Height - Weight - Force - Kelvin temp |
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1) How high you jump
2) Massed group or distributed group? |
1) Ratio
2) nominal |
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1) Right vs Left handed?
2) Score of a diver (swimming)? |
1) nominal
2) Interval |
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Goni measurement of shoulder
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Ratio
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1) Isokinetic test
2) time to run a mile |
1) ratio or interval
2) ratio |
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o Each member of population has an equal chance of being selected
o Put all names in a hat and “draw” o Table of random numbers o Become cumbersome with large populations |
simple random sampling
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o Pick every nth person from a list
o Requires a list of subjects o Ex. – choose every 10th name from a list of 1000 subjects; n = 100 |
systematic sampling
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o Used when a certain subgroup must be represented in adequate number
o Must identify stratifying characteristic |
stratified sampling
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o Frequently used in PT research
o Due to limited funding |
non-probability sampling
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o Use of readily available subjects
o Consecutive sampling – recruit patients as they become available o Volunteers o Most common sampling technique used in PT research o Problem – Self Selection We do not know what attributes are present in those who volunteer compared with those who do not Age, Motivation, Activity Level |
sample of convenience
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o Researchers identify a few subjects who are then asked to identify other potential members
o Ex. – study of patients (ACL) who all return sports activities prior to recommendation o These subjects may be able to identify others |
snowball sampling
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o Hand picking of subjects based on specific criteria
o Not based on availability (convenience) o Ex. – to test a ROM measurement tool you may specifically pick people with a variety of ROM impairments. |
purposive sampling
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o Use table of random numbers
Ex. – 32 subjects; 4 groups; First 8 go into group 1, Next 8 into group 2, etc. |
random assignment by block
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o Count off
o Frequently used o Ex. – 32 subjects; 4 groups; Count off 1 through 4 |
systematic assignment
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o Subjects are matched on important characteristics
o These subgroups are randomly assigned o Similar to stratified sampling o Ex. – 32 subjects; 4 groups; divide into male/female subgroups; then assign to groups (ex. – count off); Ensures relatively equal distribution of sex |
matched assignment
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advantages and disadvantages of matched assignment
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o Advantage: ensures equal distribution in variables that are matched (sex)
o Disadvantage: other characteristics may not evenly distribute (age, etc) |
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o Ex. – comparison of 4 post-surgery protocols
o As they enter study after surgery, they are put in next available group |
consecutive assignment
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One measurement should not precede second measurement in any systematic method
Especially when measurement is separated |
random ordering
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