Find the critical value Za/2 needed to confidence interval with the given level Level 99.7%

Question

asked Oct 23, 2023 48.7k views

1 Answer

McGordon · Answer 1 · 2023-10-28T14:12:41+0000

We looking for the value z that provides a confidence interval with a level of 99.7%, In order to find the value of Za/2 calculate

$100-99.7=0.3\Rightarrow(0.3)/(2)=0.15\Rightarrow99.7+0.15=99.85\%$

Then, look in the Z table for the z value

$P(Z\leq z)=0.9985\Rightarrow z=2.9677$

Therefore, the answer is z=2.9677.