The mean age of the 43 presidents of the United States (as of 2011) on the day of inauguration is 54.6 years, with a standard deviation of 6.3 years. A researcher constructed a 95% confidence interval for the mean age of presidents on inauguration day. He wrote that he was 95% confident that the mean age of the president on inauguration day is between 52.7 and 56.5 years of age. What is wrong to the researcher's approach to data analysis?

Question

**i dont understand this question. Any help?

Answer 1

95% = mean ± Z(SEm)

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (±.475) and its Z score. Insert Z and other data into above equations to check.