[L8] Relationship between Variables Correlation and Regression Flashcards
We are interested in finding a way to represent ___
between scores.
association
Types of Correlation
Bivariate; Multivariate Correlation
Correlation does not prove __
Causality
Multivariate Correlation have more ____ Validity
Ecological
IGT & RMT = test of difference
Correlation = test of _
_
_
correlation/association
___ – first and most obvious way to summarize
data where we are examining the relationship between
two variables
Scatterplot
We put one variable on the x-axis and another on the yaxis,
and we ___for each person showing their
scores on the two variables.
draw a point
test of correlation involved administering ___ tests in the same group of participants
2 or more different
When we want to tell people about our results, we ____
don’t
have to draw a lot of scatterplots.
__
_
_Children were asked to listen
to a word and repeat it. They were then asked which of
these 3 words started with the same sound.
Initial phoneme detection.
____reading score, a standard
measure of reading ability.
British Ability Scale (BAS)
We usually summarize and represent the relationship
between two variables with a ___
__
_
_
number (correlation
coefficient).
We also calculate the ____ for this
number, and we want to be able to find out if the
relationship is ___
Confidence Intervals; statistically significant
Thus, we want to know what is the probability of finding
a relationship at least this strong if the ____ that
there is no relationship in the population is true.
null hypothesis
– a best fitting line
used for prediction
Line of best fit or Regression Line
Predicting the variation in Y as a __
_
function of the variation
in X.
– how steep the line
*
Slope
___ – the position or height of the line.
Intercept
By convention we give the height at the point where the
line ___
hits the y-axis.
The
height is called the____or often just the
intercept
y-intercept ; (or sometimes the constant)
The intercept represents the ___of a person
who scored _
_ on the x-axis variable.
expected score ; zero
y=b0+b1X
regression expression, predicting behavior of y as function of x
useful for raw scores
It is often the case that the intercept __. After all, __no one_usually scores ___
doesn’t make any
sense; 0 or close to 0.
We can use the ___of slope and __ to
calculate the expected value of any person’s score on Y,
given their score on X.
two values, intercept