Recent content by dfraser

I'm struggling with this problem: Suppose we throw 10 standard dice. Find the probability that faces 2 and 4 occur 3 times each. I think the solution should look something like this: $$4*{10\choose3,3,4}(1/6)^3(1/6)^3(1/6)^4 + 4*{10\choose3,3,3,1}(1/6)^3(1/6)^3(1/6)^3(1/6)^1$$ $$+...

Hi, I'm struggling to know what distribution this question requires, and what should be signalling the distribution type: A manufacturer claims at most 5% of his product will sustain fewer than 1000hrs of operation before needing service. Twenty products are selected at random from the...

Thanks everyone, I understand now.

I'm given that: X is the random variable for the number of times a fair die is tossed before a six appears, and asked for E(x). I know the solution is 5 but am struggling to understand how I'm meant to get there. I understand: $$E(x) = \sum_{x=0}^{\infty} x\cdot p(x)\ $$ $$=...