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Confidence Interval for Mean

The standard deviation of test scores on a certain achievement test is 11.4. A random sample of 100 scores on this test had a mean of 71.2. Based on this sample, find a 90% confidence interval for the true mean of all scores. Complete the below:

What is the lower limit of the 90% confidence interval:___

What is the upper limit of the 90% confidence interval:___

Solution Summary

The solution provides step by step method for the calculation of confidence interval for mean . Formula for the calculation and Interpretations of the results are also included.