Data Visualization Statistical Visualization 1 — Questions and Answers
Question 1: What does a correlation matrix heatmap visualize?
- Geographic data across regions
- Pairwise correlation coefficients between multiple variables using color intensity (Correct answer)
- Frequency distributions of variables
- Time series trends across categories
Correct answer: Pairwise correlation coefficients between multiple variables using color intensity
A correlation matrix heatmap displays the correlation coefficients between all pairs of variables using color intensity to indicate strength and direction of relationships.
Question 2: What does a Q-Q (quantile-quantile) plot assess?
- Quantitative comparison between two datasets over time
- Whether a dataset follows a specific theoretical distribution, typically normal (Correct answer)
- Quartile ranges across categories
- Quality scores versus quantity produced
Correct answer: Whether a dataset follows a specific theoretical distribution, typically normal
A Q-Q plot compares the quantiles of sample data against the quantiles of a theoretical distribution; points falling on a straight line indicate the data follows that distribution.
Question 3: What statistical information does a violin plot add compared to a box plot?
- More precise quartile values
- The full probability density distribution shape of the data (Correct answer)
- Outlier labels
- Mean vs. median comparison
Correct answer: The full probability density distribution shape of the data
Violin plots add a kernel density estimate to the box plot structure, showing the full shape of the data distribution including bimodality and skewness.
Question 4: What is a 'kernel density estimate' (KDE) plot used for?
- Estimating network traffic density
- Visualizing the probability density function of a continuous variable using a smooth curve (Correct answer)
- Displaying sparse matrix data
- Calculating outlier thresholds
Correct answer: Visualizing the probability density function of a continuous variable using a smooth curve
KDE plots smooth out histogram bars into a continuous curve representing the estimated probability density function of the underlying data.
Question 5: What does a control chart (Shewhart chart) display that a regular line chart does not?
- Multiple data series
- Upper and lower control limits based on statistical variation to detect process instability (Correct answer)
- Cumulative totals over time
- Seasonal decomposition
Correct answer: Upper and lower control limits based on statistical variation to detect process instability
Control charts add statistically derived upper and lower control limits (UCL/LCL) to a time series, allowing identification of points that indicate process variation beyond normal chance.
Question 6: What is a 'pair plot' (also called scatterplot matrix) used for?
- Comparing two datasets side by side
- Visualizing pairwise relationships between all combinations of variables in a multivariate dataset (Correct answer)
- Pairing primary and secondary axes
- Displaying paired before/after data
Correct answer: Visualizing pairwise relationships between all combinations of variables in a multivariate dataset
A pair plot creates a grid of scatter plots for every combination of variables, allowing simultaneous exploration of all bivariate relationships and univariate distributions in a dataset.
Data Visualization Statistical Visualization 1
What does a correlation matrix heatmap visualize?