Fair Coin Toss Sequence?

📌 CONCEPT: The probability of an event is a measure of the likelihood of its occurrence, usually expressed as a value between 0 and 1.

📐 RULE / FORMULA: The probability of an event is calculated as the number of favorable outcomes divided by the total number of possible outcomes.

💡 WORKED EXAMPLE: If the sequence starts with HHTT and we want to find the probability that the next toss will be a tail, we have 1 favorable outcome (T) out of a total of 4 possible outcomes (H, T, H, T). So, the probability is 1/4 or 0.25.

⚠️ COMMON MISTAKE: Students often make the mistake of assuming that the probability of an event remains constant even if the sequence changes. However, in this case, the probability of a tail is 1/2 after the first toss, and 1/3 after the second toss. Only after the third toss, the probability of a tail becomes 1/2 again, which is the same as the probability of the first toss.