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A random sample of 20 observations is used to estimate the population mean. The sample mean...

A random sample of 20 observations is used to estimate the population mean. The sample mean and the sample standard deviation are calculated as 152 and 74, respectively. Assume that the population is normally distributed.

  1. What is the margin of error for a 95% confidence interval for the population mean?
  2. Construct the 95% confidence interval for the population mean.
  3. Construct the 90% confidence interval for the population mean.
  4. Construct the 78% confidence interval for the population mean. Hint: Use Excel function =t.inv.2t to find the value of t for the interval calculation.
Math   Statistics-And-Probability   
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