Data Science Statistical Concepts and Analysis 5

Question 1

Bayes' theorem allows you to update which quantity given new evidence?

Accepted Answer

The prior probability into a posterior probability

Answer

Bayes' theorem revises a prior probability into a posterior using observed evidence.

Question 2

Overfitting in a statistical model means the model:

Accepted Answer

Fits training noise and generalizes poorly to new data

Answer

Overfitting occurs when a model captures random noise in training data, hurting performance on unseen data.

Question 3

Which measure is most appropriate for describing the spread of a skewed distribution?

Accepted Answer

Interquartile range

Answer

The IQR is robust to skew and outliers, making it suitable for non-symmetric distributions.

Question 4

In hypothesis testing, increasing the sample size generally:

Accepted Answer

Increases statistical power

Answer

Larger samples reduce standard error, improving the ability to detect true effects.

Question 5

A residual in regression is defined as:

Accepted Answer

The difference between an observed and predicted value

Answer

A residual measures the error between the actual observation and the model's prediction.

Data Science Practice Test