# Thread: How many beads in a jar?

2. ## Re: How many beads in a jar?

I think you're making it harder than it is. Since you don't give us the dimensions of the jar or marbles we'll just have to accept your value of 5000 for the number of marbles.

Sample the entire outer layer of marbles. You will then have K marbles sampled resulting in C different colors and the number of marbles for each color being nc.

Your estimate for the number of marbles of each color in the jar is then going to be

$$\frac{5000}{K}n_c \mbox{ for }c=1, C$$

you simply don't have any information that indicates you can do better with some other strategy.

What you don't want to do however is process the data in pieces and then process the pieces. You want to process the raw data in one chunk.

3. ## Re: How many beads in a jar?

Thanks for the response! The actual number of beads in the jar is irrelevant for the calculation i need, I may have mislead you in my first sentence above. All i really need is the proportion of each color. The reason I didn't want to simply count all the beads visible and do a proportion from there is because that may not be truly representative of the dispersal of beads on the interior. By doing multiple samples of the same size and averaging proportions it should give a truer value so long as the same sizes are large enough, though I will likely try multiple methods and compare values