Basic Flashcards
7 cards from real DSE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Basic flashcards as text
Which measure of central tendency is most resistant to outliers?
Answer: Median
The median is resistant to outliers because it depends only on rank order, not actual values.
In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?
Answer: 68%
The empirical rule states that ~68% of data falls within ±1 standard deviation in a normal distribution.
What is the primary purpose of data normalization?
Answer: Scale features to a common range
Normalization scales features to a common range (e.g., 0–1) so no single feature dominates due to magnitude.
Which Python library is most commonly used for data manipulation and analysis?
Answer: Pandas
Pandas provides DataFrames and Series structures purpose-built for data cleaning and analysis.
What does 'variance' measure in a dataset?
Answer: The average squared deviation from the mean
Variance measures how spread out data points are by averaging their squared deviations from the mean.
A dataset with a long right tail is described as:
Answer: Positively skewed
A long right tail indicates positive (right) skewness, meaning the tail extends toward higher values.
Which file format is most commonly used to exchange tabular data between systems?
Answer: CSV
CSV (Comma-Separated Values) is the most universally supported format for simple tabular data exchange.