Question: so.. In discrete distributions, such as Bernoulli, Binomial, etc, there usually are some numbers in front of the formulas we want to answer, vertical to each other.. (i dont know how to type them here).

what do those mean, and how do we use them?

for example, in one of my questions (with negative binomial distribution) there is 10 - 1 on the top, 5-1 on the bottom, and then the formula (.5)^5 (.5)^5...

(for context, that is the probability a coin will flip head for the fifth time on the 10th trial)
  Edit

Answer: In binomial distribution , n= no. of trial. p=probability of success and q=1-p=probability of failure.
and P(X=r)and =Probability of r success from n trial=ncr*p^r *q^(n-r).


In binomial distribution , n= no. of trial. p=probability of success and q=1-p=probability of failure.
and P(X=r)and =Probability of r success from n trial=ncr*p^r *q^(n-r).

Now , In this problem n= 10 , p=1/2=0.5 given(10 trial , probability of head=0.5)
so, q=1-0.5=0.5

P(X=r)=P(X=5)=10c5*(0.5)^5*(0.5)^(10-5)=10c5*(0.5)^5*(0.5)^5=0.246=252/1024(Ans.)  Edit