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 Analysis flashcards as text
What is the primary goal of exploratory data analysis (EDA)?
Answer: To understand patterns, anomalies, and structure before modeling
EDA uncovers distributions, relationships, and data quality issues that guide later modeling.
Which technique is best for visualizing the relationship between two continuous variables?
Answer: Scatter plot
A scatter plot maps each pair of values to a point, revealing trends and correlations.
A column has 40% missing values. Which is generally the most cautious first step?
Answer: Investigate why values are missing before imputing or dropping
Understanding the missingness mechanism prevents biased imputation or unwarranted data loss.
Standardizing a feature (z-score) transforms it to have:
Answer: Mean 0 and standard deviation 1
Z-score scaling subtracts the mean and divides by the standard deviation, yielding mean 0, SD 1.
Min-max normalization rescales values to which range by default?
Answer: 0 to 1
Min-max scaling maps the minimum to 0 and the maximum to 1.
A histogram shows two distinct peaks in the data. This distribution is described as:
Answer: Bimodal
Two prominent peaks indicate a bimodal distribution, often signaling two subgroups.
Which is a sign of multicollinearity among predictor variables?
Answer: Two predictors are highly correlated with each other
Multicollinearity occurs when predictors are strongly correlated, inflating coefficient variance.