Statistical Analysis Flashcards
6 cards from real Data and Analytics practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Statistical Analysis flashcards as text
What does a z-score of 2.0 indicate?
Answer: The value is 2 standard deviations above the mean
A z-score of 2.0 means the data point is 2 standard deviations above the mean of the distribution.
What is overfitting in predictive modeling?
Answer: A model that learns training data too well and fails to generalize to new data
Overfitting occurs when a model captures noise and random fluctuations in training data, leading to poor performance on unseen data.
What is Bayes' Theorem used for?
Answer: Updating probability estimates based on new evidence
Bayes' Theorem calculates the conditional probability of an event by updating prior beliefs with new evidence.
Which distribution is characterized by a long right tail and is often seen in income data?
Answer: Right-skewed (positive skew) distribution
A right-skewed distribution has a tail extending to higher values, common in income data where most people earn moderate amounts but a few earn very high incomes.
What is the purpose of cross-validation in machine learning?
Answer: To assess how well a model generalizes to independent datasets
Cross-validation evaluates model generalization by training and testing on different subsets of data, reducing overfitting risk.
What does a chi-square test assess?
Answer: The association between two categorical variables
A chi-square test of independence evaluates whether there is a statistically significant association between two categorical variables.