SOLUTION: The standard deviation of test scores on a certain achievement test is 11. A random sample of scores on this test had a mean of 70.5. Based on this sample, find a 90% confidence i
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Question 632893: The standard deviation of test scores on a certain achievement test is 11. A random sample of scores on this test had a mean of 70.5. Based on this sample, find a 90% confidence interval for the true mean of all scores. Then complete the table below.
-what is the lower limit of the 0% confidence interval?
-what is the upper limit of the 90% confidence interval?
I am stuck on how to find the standard normal variable. But need a step by step of the entire thing to help me understand. Thank you. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! The standard deviation of test scores on a certain achievement test is 11. A random sample of scores on this test had a mean of 70.5. Based on this sample, find a 90% confidence interval for the true mean of all scores.
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x-bar = 70.5
ME = 1.645
(