Question

Which of the following is the sample space for the following experiment?
We toss a coin until we see two consecutive tails. We record the total number of coin tosses.

• A. Set of positive integers
• B. Set of natural numbers
• C. Set of natural number greater than or equal to 2
• D. None of the above

Answer 1

The correct option is C Set of natural number greater than or equal to 2

Look, I toss a coin. Either it will show a head or a tail. If it shows a head I will have to toss it again to see one of my two tails. And then at least once more to see another tail. If in the first throw itself it shows a tail, again I have to throw it once more at least to see the second tail. So in any case the coin has to be tossed at least 2 times. And then it can go on till we get two consecutive tails. So set of natural numbers greater than or equal to 2 will be the correct answer.