Pick out the wrong statement.

• Longer tubes are less expensive per unit heat transfer area as compared to shorter tubes.
• A cost index is merely a number for a given year showing the cost at that time relative to a certain base year.
• Turn over ratio of a chemical plant is the ratio of gross annual sales to the fixed capital investment.
• Plates with butt welded joints are less expensive compared to lap welded joints, because squaring of plates is not necessary.