Question

When constructing a confidence interval for a population mean with σ known, the margin of error is E = zα/2 √σ n . If you want a confidence interval at the 80% confidence level, what is the value for zα/2?

Answer 1

Step-by-step explanation

The margin of error is given by the formula

`E=Z_{(\propto)/(2)}\frac{\sigma}{\sqrt[]{n}}`

To get the value of

`\begin{gathered} Z_{(\propto)/(2)} \\ \text{from tables} \\ \end{gathered}`

The value is 1.28