Question

Help solving
Find the critical value z a/2 that corresponds to a=0.09

Answer 1

I think your question is not clear !

Answer 2

no its exactly how its written on my homework problem @amoodarya

Answer 3

so you want to find the Z value such that \(P(|Z|>z_{\alpha/2})=\alpha\); the equivalent one-tailed probability is just half of that: \(P(Z>z_{\alpha/2})=\alpha/2\) so you can look at the cdf \(P(Z<z_{\alpha/2})=1-\alpha/2\) and apply an inverse Z cdf (or equivalently look up the \(z_{\alpha/2}\) corresponding to an area of \(1-\alpha/2\) in your Z table)

Answer 4

http://www.wolframalpha.com/input/?i=invnorm&f1=1-0.09%2F2&f=NormalProbabilities.pr_1-0.09%2F2