Damian has 18 marbles in a bag. four marbles are blue, nine marbles are green, and five marbles are red. Damian randomly selected a marble from the bag, replaced it, then drew again. he repeated this for ten selections and revorded his results in the tally chart below. which experimental probabilities can damian calculate from his results? select all that apply.

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.