Statistical Concepts and Analysis Flashcards
7 cards from real Data Science practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Statistical Concepts and Analysis flashcards as text
Bayes' theorem allows you to update which quantity given new evidence?
Answer: The prior probability into a posterior probability
Bayes' theorem revises a prior probability into a posterior using observed evidence.
Overfitting in a statistical model means the model:
Answer: Fits training noise and generalizes poorly to new data
Overfitting occurs when a model captures random noise in training data, hurting performance on unseen data.
Which measure is most appropriate for describing the spread of a skewed distribution?
Answer: Interquartile range
The IQR is robust to skew and outliers, making it suitable for non-symmetric distributions.
In hypothesis testing, increasing the sample size generally:
Answer: Increases statistical power
Larger samples reduce standard error, improving the ability to detect true effects.
A residual in regression is defined as:
Answer: The difference between an observed and predicted value
A residual measures the error between the actual observation and the model's prediction.
Which of these is a discrete random variable?
Answer: Number of customers arriving per hour
Counts like the number of arrivals take whole-number values, making them discrete.
What does stratified sampling improve compared to simple random sampling?
Answer: Representation of key subgroups within the population
Stratified sampling divides the population into subgroups and samples each, ensuring better representation.