Answer:
The answer is "(27.030,29.770)"
Step-by-step explanation:
[tex](\bar{x}) = 28.4[/tex]
[tex](n)= 49[/tex]
[tex](\sigma) = 6[/tex]
[tex](CI) = \bar{x}\pm z^*_{\frac{\alpha}{2}} \frac{\sigma}{\sqrt{n}}[/tex]
[tex]z^*_{\frac{\alpha}{2}}\ for \ 89\%\ confidence = 1.598 \\\\\text{Using z table }\\\\ NORM.S.INV(1-\frac{(1-0.89)}{2})[/tex]
[tex]CI = 28.4 \pm 1.598 \times \frac{6}{\sqrt{49}}=(27.030,29.770)[/tex]
