DSE Basic 2 — Questions and Answers
Question 1: Which measure of central tendency is most resistant to outliers?
- Mean
- Median (Correct answer)
- Mode
- Range
Correct answer: Median
The median is resistant to outliers because it depends only on rank order, not actual values.
Question 2: In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?
- 50%
- 68% (Correct answer)
- 95%
- 99.7%
Correct answer: 68%
The empirical rule states that ~68% of data falls within ±1 standard deviation in a normal distribution.
Question 3: What is the primary purpose of data normalization?
- Remove duplicate records
- Scale features to a common range (Correct answer)
- Increase dataset size
- Remove null values
Correct 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.
Question 4: Which Python library is most commonly used for data manipulation and analysis?
- NumPy
- Matplotlib
- Pandas (Correct answer)
- Scikit-learn
Correct answer: Pandas
Pandas provides DataFrames and Series structures purpose-built for data cleaning and analysis.
Question 5: What does 'variance' measure in a dataset?
- The most frequent value
- The middle value
- The average squared deviation from the mean (Correct answer)
- The difference between max and min
Correct answer: The average squared deviation from the mean
Variance measures how spread out data points are by averaging their squared deviations from the mean.
Question 6: A dataset with a long right tail is described as:
- Negatively skewed
- Symmetric
- Positively skewed (Correct answer)
- Bimodal
Correct answer: Positively skewed
A long right tail indicates positive (right) skewness, meaning the tail extends toward higher values.
Question 7: Which file format is most commonly used to exchange tabular data between systems?
- JSON
- CSV (Correct answer)
- XML
- Parquet
Correct answer: CSV
CSV (Comma-Separated Values) is the most universally supported format for simple tabular data exchange.
DSE Basic 2
Which measure of central tendency is most resistant to outliers?