Question

Find a general expression of confidence interval for mean, mu, with a confident percentage 80

Answer 1

Answer

We know that the general expression for confidence interval is given as

$CI = \mu \pm z*(\sigma/\sqrt{n})$

Now, it is given that the confidence level for the required confidence interval is 80

So, z critical value corresponding to 80 confidence level is 1.28 (using z distribution table)

Setting the z value in the general equation, we get

$CI = \mu \pm 1.28*(\sigma/\sqrt{n})$

this is required general expression of confidence interval for mean, mu with a confident percentage 80.