Correlations Flashcards
what is correlational anaylsis
determine whether there is a significant linear relationship between 2 variables
what is a positive correlational analysis
as one variable increases so does the other
what is negative correlational analysis
as one variable increases, the other decreases
when you have 2 conditions, if the data is parametric, what correlation do you use
pearson
when you have 2 conditions, if the data is non-parametric, what correlation do you use
spearman
what are the 5 things you look out for with data
are there any obvious patterns is the pattern what you predicted do scores vary a lot are there any anomalies are scored clustered/spread out
what are 2 positives of using a correlation
shows a relationship
can make predictions from them
what is one negative of using a correlation
cannot draw conclusions
what 3 things does data have to have to make it parametric
interval/ratio scale
equality of homogeneity of variance
normal distribution
what are 3 positives of having parametric data
more powerful test
more likely to demonstrate of significant result
depends on parametric assumptions
what 3 things does data have to have to make it non-parametric
ordinal/nominal data
any variance
any distribution
what is a positive of having non parametric data
more tolerant of outsiders
what is a negative of having non parametric data
less powerful
what is a correlation coefficient
tells us the strength and direction of the relationship
during a correlation coefficient, what does the numbers go from
-1—–+1
in a correlation coefficient what does -1 mean
perfect negative corelation
in a correlation coefficient what does +1 mean
perfect positive corrlation
in a correlation coefficient what does 0 mean
no relationship
what can r tell us about the correlation?
the direction of the relationship-showed by - and +
strength of the relationship
what is a one tailed hypothesis
predicting the direction of the relationship
what is a 2 tailed hypothesis
predicting a relationship with no direction
what is the level of significance we accept
5%
0.05
what degress of freedom do we do
N-2
if r is larger than the critical value, then what do we do
the result is significant at p<0.5
we can be 95% certain the result did not happen by chance
we accept the experimental hypothesis and reject the null hypothesis
