15. Four friends each throw a biased coin a number of times
The table shows the number of heads and the number of tails each friend got.
Paul
heads
tails
Ben
34
8
Helen
66
12
80
40
Sharif
Paul says: "With this coin you are twice as likely to get heads as to get tails."
a) Is Paul correct? Justify your answer.
120
40
The coin is to be thrown twice.
b) Use all the results in the table to work out an estimate for the probability that the
coin will land heads both times.