Calculating the Correlation Coefficient r

What does 'bivariate' mean in the context of data?

• Data with one variable

• Data with no variables

• Data with multiple variables

• Data with two variables

How do you calculate the sample mean for a set of data points?

• Sum of all data points

• Sum of all data points divided by the number of data points

• Product of all data points

• Difference between the highest and lowest data points

What is the sample mean for the y data points 1, 2, 3, and 6?

• 2

• 3

• 4

• 5

What is the purpose of calculating the z-score for each data point?

• To find how many standard deviations a data point is from the mean

• To find the sum of all data points

• To find the product of all data points

• To find the difference between the highest and lowest data points

What is the formula for the correlation coefficient?

• Product of all data points divided by n-1

• Sum of all data points divided by n

• Difference between the highest and lowest data points divided by n

• Sum of the products of z-scores divided by n-1

What is the correlation coefficient (r) approximately for the given data set?

• 1.146

• 1.046

• 0.946

• 0.846

What does a correlation coefficient of 1 indicate?

• A random relationship between the variables

• A perfect upward sloping line describes the relationship

• A perfect downward sloping line describes the relationship

• No relationship between the variables

What does a correlation coefficient of -1 indicate?

• A perfect upward sloping line describes the relationship

• A perfect downward sloping line describes the relationship

• No relationship between the variables

• A random relationship between the variables

What does it mean if both z-scores for a data point are negative?

• The data point is an outlier

• There is a positive correlation between the variables

• There is a negative correlation between the variables

• There is no correlation between the variables

What happens to the correlation coefficient if one z-score is positive and the other is negative?

• The correlation coefficient remains the same

• The correlation coefficient increases

• The correlation coefficient becomes zero

• The correlation coefficient decreases