For Exercises 49–56, software output for confidence intervals for are provided. Assume the conditions are met. For each, examine the indicated software output, and do the following:

  1. Report the confidence interval in the form “(lower bound, upper bound).”
  2. Interpret the confidence interval.
  3. Calculate the margin of error for the confidence interval.
  4. Interpret the margin of error.

Question 8.146

49. Exam Scores. TI-83/84 output, where represents the population mean exam score. Confidence level is 95%.

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8.2.49

(a) (72.2, 77.8) (b) We are 95% confident that μ, the population mean exam score for all exam takers, lies between 72.2 and 77.8. (c) 2.8 (d) We can estimate the population mean exam score for all exam takers to within 2.8 with 95% confidence.