Pick up the incorrect statement from the following:

• A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive equantity of water
• The strength of concrete decreases as the water cement ratio increases
• If the water cement ratio is less than 0.45, the concrete is not workable and causes honey-combed structure
• Good compaction by mechanical vibrtions, increases the strength of concrete
• None of these.