4. (4 points) determine if the following are groups. if so, prove it; otherwise explain why not (a) let m be the set of symmetric 2 x 2 real matrices, with matrix multiplication (b) let qy denote the set of rational numbers which when expressed in lowest terms have denominators, and let the binary operation be addition. for the purposes of this even problem, represnt 0 as

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.

130.66 for edgedunity students

i belive false if so your welcome if not well idk