Statistics 6
If a correlation is perfect,
(not the answer) all the points must fall on a straight line
It is possible to compute a coefficient of correlation if one is given _________.
(not the answer)none of these
Which Pearson correlation coefficient shows the strongest relationship between two variables?
-.80
Which of the following values of r represents the strongest degree of relationship between two variables?
-0.80
Y can be most accurately predicted from X if the correlation between X and Y is _________.
-0.98
What is the value of the Spearman rank order correlation coefficient (rho) for the following pairs of ranks? mc054-1.jpg
0.50
What is the value of r for the following relationship between height and weight?
0.87
Which of the following statements concerning Pearson r is not true?
The relationship between the two variables must be nonlinear.
When deciding which measure of correlation to employ with a specific set of data, you should consider _________.
a and b
Which of the following is (are) not correct interpretations of Pearson r?
a and c
After several studies, Professor Smith concludes that there is a zero correlation between body weight and bad tempers. This means that _________.
a person with a bad temper may be heavy or skinny
Pearson r is _______.
all of the above
In a perfect relationship, _________.
all the points fall on the line
In a negative relationship, _________.
b is negative
A correlation coefficient expresses the direction but not the magnitude of a relationship.
false
As the value of r increases, the proportion of variability of Y that is accounted for by X decreases.
false
Given a -1.00 correlation coefficient, a raw score of 32 on one measure must be accompanied by a score of -32 on the corresponding second measure.
false
If r = -1.00, the relationship is imperfect.
false
If the relationship is imperfect, the value of the correlation coefficient must be negative.
false
In a linear relationship all the points must fall on a straight line.
false
Since r is so widely used, it is appropriate to calculate r for nonlinear data.
false
The range of a correlation coefficient is 0 to +1.
false
If the correlation between variables X and Y is 0.95, which of the following is true?
high scores on X are accompanied by high scores on Y
If N is small, an extreme score _________.
might have a large effect on robt
In order to properly use rho, the variables must be of at least _______ scaling.
ordinal
If two variables are ratio scaled and the relationship is linear, what type of correlation coefficient is most appropriate?
pearson r
The proportion of variance accounted for by a correlation between two variables is determined by _________.
r2
If a relationship is linear, _________.
the relation can be most accurately represented by a straight line
A correlation between college entrance exam grades and scholastic achievement was found to be -1.08. On the basis of this you would tell the university that _________.
they should hire a new statistician
In a perfect linear relationship all the points must fall on a straight line.
true
In a perfect positive correlation, each individual obtains the same z score on each variable.
true
In an inverse relationship as one variable gets larger the other variable gets smaller.
true
Spearman rho really derives from Pearson r.
true
The correlation between two variables when N = 2 will always be perfect.
true
The use of z scores allows comparisons between variables measured on different scales and units.
true
The value of r obtained by calculating the correlation between X and Y is the same as the correlation between Y and X.
true
Rho is used _________.
when one or both variables are only of ordinal scaling
