A researcher wishes to estimate the percentage of US seniors (65+ years of age) that are female with 91% confidence.  A random sample of 400 seniors results in 221 women and 179 men.  The 91% confidence interval for the proportion of US seniors that are female is calculated to be 0.5525±0.04210.5525±0.0421.   If the researcher wanted the above 91% confidence interval to have a margin of error (+ piece) equal to 0.03, then how many seniors should the researcher have selected? Report your answer as a whole number.

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Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.