There are four sixth graders and seven seventh graders in Elsa's chess club. Two members of the club will be chosen at random to attend a tournament with several other chess clubs. Elsa is using simulation to determine the experimental probability of randomly selecting two sixth graders. So, she places four red discs (to represent the sixth graders) and seven blue discs (to represent the seventh graders) in a bag. She randomly selects one disc from the bag, records the color, keeps the disc out, selects another disc and records it, and then returns both discs to the bag. Elsa does this twenty-five times. Her results are shown in the table below.

b, b b, r b, r b, b r, b
b, r b, b b, r b, r r, b
r, b r, r b, r r, b b, r
b, b r, r b, r r, r r, b
b, b r, r b, b r, r b, r

Based on the results of Elsa's simulation, the experimental probability of randomly selecting two sixth graders is the theoretical probability of randomly selecting two sixth graders.