I have question about a homework.
Why can we be $100\%$ sure after $4$ tests for the special case of $p=13$?
I don't get it. I have a formula that states, that every test increases certainty by $\left(\frac14\right)^k$, where $k$ is the number of tests. So after $4$ tests I get around $99.6\%$ certainty, not $100\%.$