Students in an experimental psychology lab time how long it takes rats to run a maze. Ten students run the same 20 rats. Here is the average running time (to the nearest second) for each rat:

a. Create a grouped frequency table in 10-s intervals.
b. Create a grouped frequency table in 15-s intervals.
c. Create a grouped frequency table in 20-s intervals.
d. Which table gives the clearest picture of the data?

Rat # Seconds Rat # Seconds Rat # Seconds Rat # Seconds 32 25 67 45 78 112 63 76 45 106 46 12 13 14 15 16 17 18 19 20 38 68 36 96 103 52 43 10