Isaiah recorded the grade-level and instrument of everyone in the middle school School of Rock below.
Seventh Grade Students
Instrument # of Students
Guitar 11
Bass 3
Drums 3
Keyboard 4
Eighth Grade Students
Instrument # of Students
Guitar 4
Bass 10
Drums 6
Keyboard 3

Based on these results, express the probability that an eighth grader chosen at random will play the guitar as a decimal to the nearest hundredth.