Answer:
The answer is "[tex](25.32, 30.68)[/tex]"
Step-by-step explanation:
Given:
[tex]\bar x = 28\\\\ \sigma = 4\\\\n =26\\\\[/tex]
When [tex]98\%[/tex] confidence level so, the z:
[tex]\alpha = 1 - 98\% = 1 - 0.98 = 0.2\\\\\frac{\alpha}{2} =\frac{0.02}{2} = 0.01\\\\Z_{\frac{\alpha}{2}} = Z_{0.01} = 1.645\ \ \ ( Using \ z \ table )\\\\[/tex]
[tex]E = Z_{\frac{\alpha}{2} \times ( \frac{\sigma}{\sqrt{n}})[/tex]
[tex]= 1.645 \times (\frac{4}{\sqrt{26}})\\\\=2.68[/tex]
When 98% confidence interval estimate of the population mean is,
[tex]\bar x - E < \mu < \bar x + E\\\\28 - 2.68 < \mu < 28 + 2.68\\\\25.32 < \mu < 30.68\\\\(25.32, 30.68)\\\\[/tex]
