91Ó°ÊÓ

The waiting times for patients at a walk-in clinic have a skewed distribution with a mean of 30 minutes and a standard deviation of 6 minutes. a. Using Chebyshev's theorem, find the minimum percentage of patients at this walk-in clinic who will have to wait for: j. 15 to 45 minutes ii. 12 to 48 minutes *b. Using Chebyshev's theorem, find the interval that contains waiting times of at least \(75 \%\) of the patients.

The following data give the odometer mileage (rounded to the nearest thousand miles) for all 20 cars that are for sale at a dealership. \(\begin{array}{llllllllll}62 & 86 & 58 & 84 & 72 & 40 & 27 & 38 & 50 & 43 \\\ 27 & 40 & 90 & 43 & 94 & 36 & 28 & 48 & 86 & 77\end{array}\) a. Calculate the values of the three quartiles and the interquartile range. Where does the number 77 fall in relation to these quartiles? b. Find the approximate value of the 18 th percentile. Give a brief interpretation of this percentile. c. Calculate the percentile rank of 72 . Give a brief interpretation of this percentile rank.

Melissa's grade in her math class is determined by three 100 -point tests and a 200-point final exam. To determine the grade for a student in this class, the instructor will add the four scores together and divide this sum by 5 to obtain a percentage. This percentage must be at least 80 for a grade of \(\mathrm{B}\). If Melissa's three test scores are 75,69 , and 87 , what is the minimum score she needs on the final exam to obtain a B grade?