Question

1. How many heads in a row would it take until YOU thought the coin was biased? Explain your thinking with probability.

Answer 1

An event with a probability < 0.05 is considered to be an unusual event. The probability of getting n heads in a row is computed here as:

= 0.5*0.5*0.5.... n times

Therefore we compute n here as:

For n = 4, we have: 0.5⁴ = 0.0625
For n = 5, we have: 0.5⁵ = 0.03125 < 0.05

Therefore 5 heads in a row may make us conclude that the coin is biased, as the probability of that happening is less than 0.05.