Question

Eric throws a biased coin 10 times. He gets 3 Tails. Sue throws the same coin 50 times. She gets 20 Tails. Aadi is going to throw the coin once. (i) Which one of the following statements is correct about the probability of Aadi getting Tails? (1) A Sue's estimate is best because she throws it 50 times. B Sue's estimate is best because she gets more Tails. C Sue's estimate is best because she throws it more times than Eric (ii) Use Eric's and Sue's results to work out an estimate for the probability that Aadi will get Tails. Write your fraction in the form a/b (1)​

Answer 1

(i) The correct statement about the probability of Aadi getting Tails is B - Sue's estimate is best because she gets more Tails. The number of times a coin is flipped affects the accuracy of the probability estimate, but getting more Tails in fewer trials does not necessarily mean that the probability of getting Tails is higher.

(ii) Eric got 3 Tails in 10 trials, so the proportion of Tails is 3/10. Sue got 20 Tails in 50 trials, so the proportion of Tails is 20/50 or 2/5. We can use the average of these two proportions as an estimate for the probability that Aadi will get Tails.

(3/10 + 2/5) / 2 = 0.35

So the estimated probability of Aadi getting Tails is 0.35 or 7/20 in fraction form.