Calculate confidence interval when only given alpha? Is there

Alisa Duarte

Alisa Duarte

Answered question

2022-03-17

Calculate confidence interval when only given alpha?
Is there a formula to properly calculate the confidence interval when you're only given alpha and sample data?

Answer & Explanation

Kasen Alexander

Kasen Alexander

Beginner2022-03-18Added 7 answers

In order to correctly construct confidence interval, first of all, you need a "pivot" T such that
1. T is a function of all data X1,X2,,Xn.
2. T is a function of μ
The distribution of T is know, and it is not a function of μ
For example, T=xμσn is a pivot, and TN(0,1) regardless of the value of μ (if the sample size is large enough, say >30).
In this case, P(aTb)=1α, where a=Zα2 and b=Zα2. So the "natural" confidence interval is (xZα2(σn),x+Zα2(σn)), where Zα2 is such that P(z>Zα2)=α2.
Zα2 can be calculated using the R command q1α2
This is just an example when we know the pivot has the normal distribution. There exist other cases where the pivot we constructed doesn't have a normal distribution, and the calculation in that case would be a little bit different than this. I don't think there exists a formula that can be applied to any situation.

Do you have a similar question?

Recalculate according to your conditions!

New Questions in College Statistics

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?