# Expectation with confidence

#### olivier123

##### New Member
Hello,

It has been a while since I used my probability and statistics. My question is:
Say a group of 5 five people need to find the similarities between two foto's individually. After checking the result is that they found 3, 6, 2, 8, 1 correct similarities. How can you say with a certain probability what the actual number of similarities is? I think it has something to do with confidence interval?

All help is appreciated!

#### fed2

##### Active Member
All help is appreciated!
Lets put that to the test...

After checking the result is that they found 3, 6, 2, 8, 1 correct similarities.
were they the same similiarity? seems important

You know, i think this has the flavor of a 'mark recapture' experiment you see in ecology sometimes, and i wonder if similar statistics/methodlogy could not be applied? I say that because you are interested in estimating the size of a population, sort of. Well, you could sort of take the view that the first persons corrects are a mark, and the second is a recapture of those marks thing. Maybe there is a simpler answer just isn't clicking right now. well good luck, and may the stats gods shine there countenance on this experiment.

#### joeb33050

##### Member
Hello,

It has been a while since I used my probability and statistics. My question is:
Say a group of 5 five people need to find the similarities between two foto's individually. After checking the result is that they found 3, 6, 2, 8, 1 correct similarities. How can you say with a certain probability what the actual number of similarities is? I think it has something to do with confidence interval?

All help is appreciated!
Since there were 8 correct similarities found, the total number of similarities is 8 or greater. Throw out the other 4 incorrect answers. Then you know one thing: "A person found 8 similarities."
It's time to define your question, then figure out how to find the answer. It is not time, in my (slightly) humble opinion, to think about confidence intervals or any sophisticated statistical techniques.
One person found 8 similarities. That's all you know.
joe b.