Exercise 4.20:
The ministry of Health and Long-Term Care in Ontario, Canada publishes information on the time that patients must wait for various medical procedures on its web site (www.health.gov.on.ca). For two cardiac procedures completed in fall of 2005 the following information was provided:

Procedure	Number of Completed Procedures	Median Wait Time (days)	Mean Wait Time (days)	90% Completed Within (days)
Angioplasty	847	14	18	39
Bypass surgery	539	13	19	42

a. Which of the following must be true for the lower quartile of the data set consisting of the 847 wait times for angioplasty?
     i. The lower quartile is less than 14.
     ii. The lower quartile is between 14 and 18.
     iii. The lower quartile is between 14 and 39.
     iv. The lower quartile is greater than 39.
b. Which of the following must be true for the upper quartile of the data set consisting of the 539 wait times for bypass surgery?
     i. The upper quartile is less than 13.
     ii. The upper quartile is between 13 and 19.
     iii. The upper quartile is between 13 and 42.
     iv. The upper quartile is greater than 42.
c. Which of the following must be true for the 95th percentile of the data set consisting of the 539 wait times for bypass surgery?
     i. The 95th percentile is less than 13.
     ii. The 95th percentile is between 13 and 19.
     iii. The 95th percentile is between 13 and 42.
     iv. The 95th percentile is greater than 42.

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