Respuesta :
Answer:
The minimum sample size required to create the specified confidence interval is 1024.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1-0.98}{2} = 0.01[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].
So it is z with a pvalue of [tex]1-0.01 = 0.99[/tex], so [tex]z = 2.327[/tex]
Now, find the margin of error M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
What is the minimum sample size required to create the specified confidence interval
This is n when [tex]M = 0.08, \sigma = \sqrt{1.21} = 1.1[/tex].
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
[tex]0.08 = 2.327*\frac{1.1}{\sqrt{n}}[/tex]
[tex]0.08\sqrt{n} = 2.327*1.1[/tex]
[tex]\sqrt{n} = \frac{2.327*1.1}{0.08}[/tex]
[tex](\sqrt{n})^{2} = (\frac{2.327*1.1}{0.08})^{2}[/tex]
[tex]n = 1024[/tex]
The minimum sample size required to create the specified confidence interval is 1024.
