-vvn'- 7 W To estimate'a population parameter (such as the population mean or population proportion) using a confidence interval first requires one to . :calcUIate the margin of error, E. The value of the margin of error, E, can be calculated using the appropriate formula. The formula depends on whether one is estimating a mean or estimating a proportion. ,a. The Margin of Error, E, for a 95% confidence interval for means is: E_ \"r\" 1323 where sis the sample standard deviation and n is the sample size. ivnt-a quantitative variable, such as age, weight, exam score, etc. king about that variable, create a small set of data (30 data values] fribe that variable. Use Excel to calculate the sample mean of d the sample standard deviation. If you create 30 value ' 5330 Then, calculate the margin of error