Question 1
Explain what the phrase 95% confident means when we interpret a 95% confidence interval for
μ.
◦ 95% of similarly constructed intervals would contain the value of the sampled mean.
◦ The probability that the sample mean falls in the calculated interval is 0.95.
◦ 95% of the observations in the population fall within the bounds of the calculated interval.
◦ In repeated sampling, 95% of similarly constructed intervals contain the value of the population mean.
Question 2
Parking at a large university can be extremely difficult at times. One particular university is trying to determine the location of a new parking garage. As part of their research, officials are interested in estimating the average parking time of students from within the various colleges on campus. A survey of 338 College of Business (COBA) students yields the following descriptive information regarding the length of time (in minutes) it took them to find a parking spot. Note that the "Lo 95%" and "Up 95%" refer to the endpoints of the desired confidence interval.
Variable N
Lo 95% CI Mean Up 95% CI SD
Parking Time 338 9.1944 10.466 11.738 11.885
University officials have determined that the confidence interval would be more useful if the interval were narrower. Which of the following changes in the confidence level would result in a narrower interval?
◦ The university could increase their confidence level.
◦ The university could decrease their confidence level.
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Illustration of a large aneurysm in the abdominal aorta that has ruptured.
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