The World Health Organization estimates (based on death certificates) that the distribution of ages at death in the United States has a mean of 79.8 years and standard deviation of 15.5 years. Suppose those are the true values. a) Would you expect age at death to be a left-skewed, right-skewed, or symmetric distribution? Explain briefly. It may be useful to consider what ages of death are common, which are less common, and which are impossible. b) Researchers plan to collect random samples of 64 United States death certificates and calculate the sample mean age at death, ?̅ , for each sample. Would you expect the sampling distribution of age at death, ?̅ , to have a left-skewed, right-skewed, or symmetric distribution? Explain briefly. c) In approximately what proportion of samples would ?̅ be less than 78 years? d) Now suppose that the sample size is increased to 400 death certificates per sample. In what proportion of samples would ?̅ be less than 78 years?
The World Health Organization estimates (based on death certificates) that the distribution of ages at death in the
United States has a
a) Would you expect age at death to be a left-skewed, right-skewed, or symmetric distribution? Explain briefly.
It may be useful to consider what ages of death are common, which are less common, and which are impossible.
b) Researchers plan to collect random samples of 64 United States death certificates and calculate the sample
mean age at death, ?̅ , for each sample. Would you expect the sampling distribution of age at death, ?̅ , to have a
left-skewed, right-skewed, or symmetric distribution? Explain briefly.
c) In approximately what proportion of samples would ?̅ be less than 78 years?
d) Now suppose that the
samples would ?̅ be less than 78 years?
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