TIBCO Spotfire Analytics and Statistics 1 — Questions and Answers
Question 1: In TIBCO Spotfire, what does adding a 'Trend Line' to a scatter plot provide?
- Connects all points with a line
- Fits a mathematical model (e.g., linear, polynomial) to show data trends (Correct answer)
- Groups points into clusters
- Adds error bars to each point
Correct answer: Fits a mathematical model (e.g., linear, polynomial) to show data trends
A trend line fits a regression model to the scatter plot data, visually indicating the overall direction and rate of change.
Question 2: Which statistical curve type in Spotfire's trend line fits data that grows or decays exponentially?
- Linear
- Exponential (Correct answer)
- Polynomial
- Logistic
Correct answer: Exponential
An exponential curve fits data where the rate of change is proportional to the current value, such as population growth.
Question 3: What does Spotfire's 'Confidence interval' band around a trend line represent?
- The range of all data points
- The uncertainty range within which the true regression line likely falls (Correct answer)
- The standard deviation of residuals
- The prediction range for new individual data points
Correct answer: The uncertainty range within which the true regression line likely falls
The confidence interval band shows the range where the true mean response line falls with a specified probability (e.g., 95%).
Question 4: In Spotfire, what does 'Prediction band' show on a trend line chart?
- The model's R² value visually
- The range within which a new individual data observation is expected to fall (Correct answer)
- The historical variance of the training data
- The confidence interval for the mean
Correct answer: The range within which a new individual data observation is expected to fall
A prediction band is wider than a confidence interval and shows where individual future data points are expected to land.
Question 5: What statistic does Spotfire display as R² on a trend line, and what does it indicate?
- Regression coefficient showing slope steepness
- Coefficient of determination showing how much variance in Y is explained by X (Correct answer)
- Pearson correlation coefficient
- Root mean square error of the fit
Correct answer: Coefficient of determination showing how much variance in Y is explained by X
R² (coefficient of determination) ranges from 0 to 1 and indicates what fraction of the dependent variable's variance the model explains.
Question 6: In Spotfire, which aggregation method computes the middle value of a sorted dataset?
- Avg
- Median (Correct answer)
- StdDev
- Sum
Correct answer: Median
Median returns the 50th percentile — the value at the midpoint of a sorted list, robust to outliers.
TIBCO Spotfire Analytics and Statistics 1
In TIBCO Spotfire, what does adding a 'Trend Line' to a scatter plot provide?