Stats Topic 2

Question 1

Correlation

Answer 1

measures the strength and direction of the relationship between two numerical variables.

Question 2

Positive correlation

Answer 2

Both variables increase together.

Question 3

Negative correlation

Answer 3

One variable increases while the other decreases.

Question 4

No correlation

Answer 4

No systematic relationship between variables.

Question 5

correlation coefficient (r)

Answer 5

quantifies this relationship, ranging from -1 (perfect negative correlation) to +1 (perfect positive correlation). A value close to 0 indicates little or no linear relationship.

Question 6

Sampling variability

Answer 6

refers to the natural fluctuations in statistical measures when different samples are taken from a population.

Question 7

Affecting Sampling Variability

Answer 7

• It affects the stability of correlation coefficients—smaller samples show more variability.
• Larger samples reduce sampling error and yield correlation estimates closer to the true population value.
• Research relies on inferential statistics to estimate population patterns based on sample data.

Question 8

Statistical tests

Answer 8

assess whether an observed correlation is likely to exist in the population or if it occurred by chance.

Question 9

The null hypothesis (H₀)

Answer 9

states there is no correlation in the population.

Question 10

The alternative hypothesis (H₁)

Answer 10

suggests a real correlation exists.

Question 11

p-value

Answer 11

indicates the probability that the observed correlation is due to random chance

Question 12

Degrees of freedom (DF)

Answer 12

in correlation tests are calculated as N - 2, where N is the sample size.