Fact or Bluff Quiz

The Pearson correlation coefficient (r) can only take values between -1 and 1.

• Fact

• Bluff

If the computed t-value is greater than the critical t-value, we accept the null hypothesis.

• Fact

• Bluff

Answer explanation

If t-computed is greater than t-critical, we reject the null hypothesis.

A strong positive correlation means that one variable causes the other to increase.

• Fact

• Bluff

Answer explanation

Correlation does not imply causation.

The degrees of freedom for the t-distribution in correlation testing is calculated as n - 2.

• Fact

• Bluff

If the p-value in a correlation test is less than the significance level (α), we conclude that the correlation is statistically significant.

• Fact

• Bluff

The t-distribution is used in hypothesis testing when the population standard deviation is unknown and the sample size is small.

• Fact

• Bluff

A correlation of 0 always means that there is no relationship between two variables.

• Fact

• Bluff

Answer explanation

A correlation of 0 means no linear relationship, but there could be a non-linear relationship.

If the correlation coefficient for the paired variables X and Y is positive, then Y will tend to decrease as X increases.

• Fact

• Bluff

Answer explanation

Y will tend to increase as X increases or Y will decrease as X also decreases.

If the t-value is 2.15, degrees of freedom is 19 and α=0.01 (two-tailed test); then the interpretation is significant.

• Fact

• Bluff

Answer explanation

Not significant since the tabular t is 2.8609 which is higher than the computed t-value of 2.15.