A new ferilizer was tested on fields of corn. Researchers randomly selected 5 of 10 similar fields to receive the new fertilizer, and the other 5 fields received the old fertilizer. At the end, the yield of corn was recorded and compared.

What are the factor/s and level/s?

• 1 factor: fertilizer, 2 levels: old and new
• 2 factors: old and new fertilizer, 1 level: corn
• 10 factors: fields of corn, 2 levels: old and new fertilizer
• 1 factor: fields, 2 levels: old and new fertilizer