The popularity of computer, video, online, and virtual reality games has raised concerns about their ability to negatively impact youth. the data in this exercise are based on a recent survey of 14 ‑ to 18 ‑year‑olds in connecticut high schools. assume the table displays the grade distributions of boys who have and have not played video games.
grade average
a's and b's c's d's and f's
played games 730 444 190
never played games 214 137 87
give the conditional distribution of the grades of those who have played games. (enter your answers rounded to two decimal places.)

An annual marathon covers a route that has a distance of approximately 26 miles. winning times for this marathon are all over 2 hours. the following data are the minutes over 2 hours for the winning male runners over two periods of 20 years each. earlier period 14 12 15 22 13 10 19 13 9 14 20 18 16 20 23 12 18 17 6 13 recent period 7 11 7 14 8 9 11 14 8 7 9 8 7 9 9 9 9 8 10 8 (a) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the earlier period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks. for more details, view how to split a stem.) minutes beyond 2 hours earlier period 0 1 2 (b) make a stem-and-leaf display for the minutes over 2 hours of the winning times for the recent period. use two lines per stem. (use the tens digit as the stem and the ones digit as the leaf. enter none in any unused answer blanks.) minutes beyond 2 hours recent period (c) compare the two distributions. how many times under 15 minutes are in each distribution