Q.The annual turnover (₹ lakh) of five small firms in a Gujarat industrial estate is: Firm A 40, Firm B 65, Firm C 30, Firm D 80, Firm E 55.

Since only one variable (turnover) is being compared across five separate firms, a simple bar diagram is the natural choice.

1. Choice of diagram. The data has only one variable (annual turnover) measured across five discrete categories (the five firms) — there is no sub-division within each firm's figure, and no second variable to compare alongside it. This is exactly the situation a simple bar diagram is designed for; a multiple bar diagram would be needed only if, say, both this year's and last year's turnover were being compared per firm, and a sub-divided bar diagram would be needed only if each firm's turnover were itself split into components (e.g., domestic vs export sales).
2. Construction.

1. Draw a horizontal x-axis (firms: A, B, C, D, E) and a vertical y-axis (turnover, ₹ lakh), with the y-axis starting at zero so that bar heights are honestly comparable.
2. Choose a uniform bar width and a uniform gap between bars (about half the bar width).
3. Draw one bar per firm, with height equal to its turnover: A = 40, B = 65, C = 30, D = 80, E = 55.
4. Label each bar with the firm's name below the x-axis, and optionally write the exact value at the top of each bar.
5. Give the diagram a clear title (e.g., 'Annual Turnover of Five Firms in a Gujarat Industrial Estate, ₹ lakh') and label both axes with their units.

A common mistake is starting the y-axis at a value other than zero to 'zoom in' on small differences — this visually exaggerates the comparison and is considered a misleading diagram, never acceptable in a statistics answer.