EBP PROCESS
association
how measures relate, they have a relationship
* correlation has some degree of association (direction + magnitude)
* provides limited information on reliability
does correlation have association
has some degree of association (direction + magnitude)
does association provide information on reliability
provides LIMITED information on reliability
agreement
directly proportional/consistent
* perfect correlation
describe agreement correlation
perfect correlation
correlation
determines whether (p-value) + to what degree (magnitude) a relationship exists between 2 or more quantifiable variables
* are variables related?
correlation-
things to consider
-positive or negative associations- DIRECTION
-strong or weak associations- MAGNITUDE
direction
positive or negative associations
magnitude
strong or weak associations
Pearson product moment correlation (Pearson Correlation) measures what
measures the strength of association between continuous variables (ROM, 0-100 scale, etc.)
-aka magnitude
Pearson product moment correlation (Pearson Correlation) ranges from
-1.0 to 1.0
Pearson product moment correlation (Pearson Correlation)- PARAMETERS
-population parameter, “p”
-sample parameter, “r”
Pearson product moment correlation (Pearson Correlation)-
which parameter are we usually focused on
sample parameter, “r”
see table on page 2 of Emily study guide + INTERPRETATION
pearson correlation (r) of 0.923 indicates…
strong, positive correlation
-because it is close to 1.0
significance (2-tailed) of 0.000 indicates…
(if correlation is significant at the 0.01 level (2-tailed))
p-value is less than 0.01
example of what to write for interpretation of correlations table question
“there is a strong, positive correlation between post-concussion symptom catastrophizing + anxiety (r = 0.923)”
example of what to write for probability interpretation/statistical significance using p-value of correlations table question
“there is less than 1% chance of no association between post-concussion symptom catatrophizing + anxiety (p less than 0.01)”
*remember less than alpha is statistically singificant
p value less than alpha =
statistically significant
significance of correlation coefficient
-observed “r” is one of infinite number of possible correlation
-statistical significance is observed, NOT due ot chance
* statistical significance DOES NOT mean a strong relationship because it provides no information about the magnitude of the relationship
does statistical significance mean a strong relationship?
NO
-because it provides no information about the magnitude of the relationship
coefficient of determination
r^2