Setup
Region and z-scores
Probability controls
Switch the question type, then move the cutoff values with the sliders or by dragging directly on the graph.
Classroom-ready examples
Jump to a common prompt with one click.
Visualization
Normal curve and shaded region
Drag the shaded region or its cutoff lines to update the z-score directly from the graph.
The blue area is the probability requested by the current z-score statement.
In the between case, drag inside the band to shift both cutoffs together.
Area readout
The symbolic question and shaded probability update together.