We have to assume that the sample mean is given , distribution is normal and sample size is also given.
Given confidence level 99%.
We have to answer the assumptions that are needed to make a valid 99% confidence interval.
Confidence interval can be made by formula of margin of error.
Margin of error is the difference between actual values and the calculated values.
Upper level of confidence interval=Mean+ margin of error
Lower level of confidence interval= Mean - margin of error.
Margin of error=z*σ/[tex]\sqrt{n}[/tex]
where z is the corresponding z value for the confidence level given ,
σ is population mean and n is sample size.
Hence to calculate the confidence interval we need population mean, sample size.
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