Statistics II

Drawing Pie Diagram :

• Find measure of central angle using formula (x / Total f_i).360⁰.
• Draw central angles on circle of convenient radius.

Drawing Histogram :

• Make class intervals continuous.
• Take extended class intervals on X-axis.
• Take frequencies on Y-axis.
• Draw rectangles on X-axis with base as extended class intervals.

Drawing Frequency Polygon or Frequency Curve :

• Prepare frequency distribution table.
• Draw X-axis, Y-axis, choose proper scale.
• Take class marks on X-axis.
• Take frequencies on Y-axis.
• Plot the points.
• Plot 2 additional points, one preceding the first class and another succeeding the last class, both with frequency 0.
• In case of Frequency Polygon, join all successive points by straight lines.
• In case of Frequency Curve, join all successive points by smooth freehand curve.