一道英文的统计课作业题目Independentflipsofacointhatlandsonheadswithprobabilityparemade.WhatistheprobabilitythatthepatternT,H,H,HoccursbeforethepatternH,H,H,H?Hint:HowcanthepatternH,H,H,Hoccurfirst?

Question

一道英文的统计课作业题目
Independent flips of a coin that lands on heads with probability p are made.
What is the probability that the pattern T, H, H, H occurs before the pattern H, H, H, H?
Hint: How can the pattern H, H, H, H occur first?
然后现在在学的是conditional probaility

Answer 1

P(THHH|HHHH)=P(THHHHHHH)/P(HHHH)
=(1-p)p^7/p^4
=(1-p)p^3