Double Staircase Histogram

When a histogram looks like a double staircase, it is because:

Correct Answer Explanation

Sometimes the common portion between two adjacent rectangles is omitted, giving a better impression of continuity. The resulting figure gives the impression of a double staircase.

Key Points:

• This happens when the histogram is drawn by omitting overlapping edges.
• It provides a cleaner visual appearance.
• The adjacent rectangles share a common class boundary.
• This convention improves readability of the histogram.

Why Other Options Are Wrong

• A. Too many classes: Number of classes doesn't cause a staircase effect.
• C. Unequal intervals: Unequal intervals require frequency density, not staircase.
• D. Frequency density: This is an adjustment for unequal intervals, not appearance.