A random sample of 1000 people was taken and a 95% confidence interval for the average income in thousands is (30, 70). What would be a 90% confidence interval based on the same sample? Assume the...

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Extracted text: A random sample of 1000 people was taken and a 95% confidence interval for the average income in thousands is (30, 70). What would be a 90% confidence interval based on the same sample? Assume the population standard deviation o is known. Show your work. (Hint: the sample mean is the center/midpoint of the confidence interval)