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Hitting a barrier · Part 3 of 4
is a standard Brownian motion started at 0, with no drift. The parts ask about the first time it reaches given levels.
Now add a lower barrier at −2. What is the probability of reaching +1 before −2?
Answer with a number. Fractions, powers and expressions like 23/6 or C(52,5) are read correctly in practice.
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Hitting times, the reflection principle and the running maximum
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