1. The average life expectancy of people around the world is 71.30 years with a population standard deviation of 8.00 years. I take a sample of 50 countries now and find that the average life expectancy is 74.37 years. Suppose I’m interested in seeing if there has been a significant increase in the life expectancy.
a. What is the standard error?
b. What is the margin of error at 90% confidence?
c. Using my sample of 50, what would be the 90% confidence interval for the population mean?
d. If I wanted to control my margin of error and set it to 1 at 95% confidence, what sample size would I need to take instead of the 50?
e. What are the null and alternative hypotheses?
f. What is the critical value at 90% confidence?
g. Calculate the test statistic.
h. Find the p-value.
i. What conclusion would be made here at the 90% confidence level?
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