What does a correlation coefficient measure?

• Causation

• Strength and direction of a linear relationship

• The standard deviation

• The mean

Which correlation coefficient measures the relationship between two continuous variables when the data is not normally distributed?

• Pearson correlation coefficient

• Spearman rank correlation coefficient

• Point-biserial correlation coefficient

• Biserial correlation coefficient

If the Pearson correlation coefficient is -0.85, what does this indicate about the relationship between two variables?

• Strong positive correlation

• Strong negative correlation

• Weak positive correlation

• No correlation

When the correlation coefficient is 0, it means:

• A perfect positive correlation

• A perfect negative correlation

• No linear relationship

• Non-linear relationship

What is the range of values for the Pearson correlation coefficient?

• -1 to 1

• 0 to 1

• -∞ to ∞

• 0 to 100

In a scatter plot, if points are scattered randomly with no discernible pattern, what is the likely value of the correlation coefficient?

• 1

• -1

• 0

• 0.5

Which correlation coefficient is more appropriate when dealing with ordinal data?

• Pearson correlation coefficient

• Biserial correlation coefficient

• Point-biserial correlation coefficient

• Spearman rank correlation coefficient

If a correlation coefficient is close to 1, it indicates:

• A strong negative correlation

• A strong positive correlation

• A weak correlation

• No correlation

What is the main limitation of the Pearson correlation coefficient?

• It assumes a linear relationship

• It cannot be calculated for nominal data

• It always ranges between -1 and 1

• It is not affected by outliers

Rank correlation is used to measure the association between variables when:

• Variables are continuous

• Variables are categorical

• Data is ranked rather than measured

• Data is normally distributed