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.
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?
**i dont understand this question. Any help?
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