PSYC1040 Correlations

It is unsuitable or inadvisable to use Pearson's r when:

• the relationship is linear

• the relationship is non-linear

• there are no extreme scores or outliers

• both variables have been measured on a ratio scale

• both variables have been measured on an interval scale

Which of the following does not apply to Pearson's r?

• It is not sufficient to establish causal links between variables

• Is not sensitive to curvilinear relationships.

• It is the square root of the coefficient of determination

• It is a measure of the extent to which paired scores occupy the same or opposite positions within their distributions

• It is relatively insensitive to outliers

Which of the following scatterplots of X and Y scores would yield the highest absolute value (i.e., ignoring the + or - sign) of Pearson’s r?

• 1

• 2

• 3

• 4

• 5

The value of Pearson’s r for this scatterplot would be approximately...

• +.50

• -.50

• +1

• 0

• -1

The value of Pearson’s r for this scatterplot would be approximately...

• +.5

• -.5

• +1

• 0

• -1

Which scatterplots would best represent the relationship between a person's intelligence and the number (1 to 31) of the day of the month of their birth?

• 1

• 2

• 3

• 4

• 5

•Which of the relationships shown are negative relationships?

• 2 and 4

• 4 and 5

• 3 and 5

• 3 and 4

• 1 and 2

If the correlation between two variables, X and Y, is r = -0.9 then this means that:

• values above the mean on X pair with values below the mean on Y

• 81% of the variance in Y is related to the variance in X and 81% of the variance in X is related to the variance in Y

• the data points will cluster closely along a straight line

• the slope of the ‘line of best fit’ is negative

• all of the above