Data Science Statistical Concepts and Inference 3

Question 1

For a strongly right-skewed income distribution, which measure of central tendency best represents a typical value?

Accepted Answer

Median

Answer

The median is resistant to extreme values and better reflects the typical observation in skewed data.

Question 2

A correlation coefficient of -0.9 indicates:

Accepted Answer

A strong negative linear relationship

Answer

A coefficient near -1 indicates a strong negative linear association.

Question 3

Which statement about correlation and causation is correct?

Accepted Answer

Correlation can arise from a confounding variable without direct causation

Answer

Two variables can be correlated due to a lurking confounder rather than one causing the other.

Question 4

In a normal distribution, approximately what percentage of values fall within two standard deviations of the mean?

Accepted Answer

95%

Answer

The empirical rule states about 95% of data lies within two standard deviations of the mean.

Question 5

A z-score of 0 means the observation is:

Accepted Answer

Exactly at the mean

Answer

A z-score of 0 indicates the value equals the mean.

Data Science Practice Test