Well, finally finished my assignement! Here's my stumbling block though: How to tell what methods or equations to use when a problem is posed?! I find I stare at the question and struggle with which way to go. For instance, one of the questions went like this:
'Supose you are interested in the proportion p of defective items being produced by a manufacturing process. You suspect that p is fairly small and inspect 50 items but find no defectives. Using 0 as an estimate is not particularly useful. It would be more useful if we could put an upper limit on p, for example, "we are fairly sure p is no bigger than 0.07"
a) what is the distribution of X, the number of defectives in a sample of 50?
b) What assumptions are implicit in your answer to a? Give some circumstances in which they wouldn't be valid.
I noticed key words such as proportion and distribution of X and so assumed this was discussing a binomial distribution. I answered a as X~binomial(n,p) and in b said that we are assuming n=50 is less than 0.1 of the total pop.
I wasn't really sure though that what I was saying wasn't just a guess.
I guess my worry is that when I get to an exam I won't be able to figure out what to do!
E

The biggest clue is:

"You suspect that p is fairly small..."

This would lead me to believe that it follows a Poisson distribution.

Hi- I know this is an OLD post, but I am struggling with this same problem. I am brand new to stats of any sort, and am trying very hard to figure out what to do in any given situation. Is the distribution of X going to require me to use the binomial distribution formula? How do I find my p to plug in? How to I make a rational estimate? In my course, we have not covered Poisson distribution, so I would be surprised if I am expected to use it. Once I figure out part a), I have no problem with part b). But in the meantime, I am totally lost. Any direction would be appreciated!

Thank you

~L