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# Chi Square Test

1. Hi, I've been going over past exam problems, and I'm really struggling with Chi Square tests. I just don't really know whats going on.

Specifically:
Questions:

Solutions:

So for part b) Is the number of degrees of freedom always n-1? I don't see what the answers mean by 3 entries, 1 constraint. Does that mean, if you were to put it in a table, there would be 3 items and 1 property they have? I.e 3 colours and a number attached to each?

For part c), from what I remember, the probability of a type I error is equal to that of being in the rejection region. Does that apply here too?

Part d) I get this, we want to test if the distribution is how they say it is. What I don't understand is why we are only performing a single tail test. This relates to part b) because in the answers he has written (in brackets) "one sided." I don't understand this at all, I knew how to picture it with a normal distribution. I'm finding it more difficult with this.

In short, my main question is why are we performing a single tail test?

Thanks for any help!
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