Please choose the correct answer to the question: A student flips a coin four times. It lands "heads" up three times. The student concludes that the coin will land "heads" up three times out of four. What will make the conclusion more accurate?

Answer1: substituting a different coin Answer2: flipping the coin twenty more times Answer3: taping a weight to one side of the coin Answer4: flipping the coin over a smoother surface

Answer format: answer1/answer2/answer3/answer4
Answer: answer2