Data Visualization Statistical Visualization 2 β Questions and Answers
Question 1: What does skewness indicate about a data distribution when visualized as a histogram?
- The number of outliers present
- The degree and direction of asymmetry around the distribution's central value (Correct answer)
- The variance of the dataset
- The presence of multiple modes
Correct answer: The degree and direction of asymmetry around the distribution's central value
Positive skewness shows a long right tail (most values cluster left), while negative skewness shows a long left tail (most values cluster right).
Question 2: In a box plot, what do the 'whiskers' typically represent?
- The mean and one standard deviation
- Data points within 1.5 Γ IQR from the first and third quartile (Correct answer)
- The minimum and maximum values always
- The 5th and 95th percentiles
Correct answer: Data points within 1.5 Γ IQR from the first and third quartile
By default (Tukey's method), box plot whiskers extend to the most extreme data points within 1.5 times the interquartile range (IQR) from Q1 and Q3.
Question 3: What is the primary use of a funnel chart in business analytics?
- Show temperature gradients
- Visualize the progressive reduction of values through sequential stages of a process (Correct answer)
- Compare budget versus actual values
- Display geographic density data
Correct answer: Visualize the progressive reduction of values through sequential stages of a process
Funnel charts show drop-off rates through sequential stages (e.g., sales pipeline or conversion funnel), with width proportional to the number of items remaining at each stage.
Question 4: What does a residual plot in regression analysis reveal?
- The correlation between independent variables
- Whether the linear regression model adequately fits the data by showing patterns in errors (Correct answer)
- The significance of each predictor variable
- The R-squared value of the model
Correct answer: Whether the linear regression model adequately fits the data by showing patterns in errors
Residual plots show the difference between observed and predicted values; random scatter indicates a good fit, while patterns suggest model inadequacy or violated assumptions.
Question 5: What is the purpose of 'confidence interval bands' on a trend line visualization?
- Show the minimum and maximum data values
- Indicate the uncertainty range within which the true trend line is likely to fall (Correct answer)
- Display the interquartile range of residuals
- Mark statistically significant data points
Correct answer: Indicate the uncertainty range within which the true trend line is likely to fall
Confidence interval bands (typically 95% CI) around a trend line show the range of values within which the true underlying trend is statistically likely to fall.
Question 6: What is a 'parallel coordinates plot' used for in multivariate data visualization?
- Displaying data along parallel x-axes
- Visualizing multiple quantitative variables simultaneously to reveal patterns and clusters across high-dimensional data (Correct answer)
- Comparing two datasets in parallel
- Showing parallel time series
Correct answer: Visualizing multiple quantitative variables simultaneously to reveal patterns and clusters across high-dimensional data
Parallel coordinates plots use vertical axes for each variable, with each data record drawn as a polyline connecting its values across all axes, enabling high-dimensional pattern detection.
Data Visualization Statistical Visualization 2
What does skewness indicate about a data distribution when visualized as a histogram?