Answer:
The probability mass function is expressed as:
P(x) = [(x+r-1)C(r-1)]*[p^r]*[(1-p)^x]
Step-by-step explanation:
This is not a binomial distribution. It is actually a negative binomial distribution. The probability mass function is expressed below:
P(x) = [(x+r-1)C(r-1)]*[p^r]*[(1-p)^x]
where:
x = number of failures
r-1 = number of successes (10 in this scenario)
p = probability of a success
nCr = n!/[r!(n-r)!]
The main formula difference in the positive binomial versus negative binomial is this: With respect to the negative binomial, it is obviously known that the last event will be: when we reach our 10th "head", we stop .
Thus, the last flip will ALWAYS be a "head".