The experimental probability of choosing a blue marble from the bag is 30%.
Step 1: Calculate the number of blue marbles in the bag
Since the bag contains an equal number of blue, red, and green marbles, and there are a total of 12 marbles, there must be 12 / 3 = 4 blue marbles in the bag.
Step 2: Calculate the number of times a blue marble was chosen
The problem states that Marnie conducted the experiment for a total of 20 trials. We are not given any specific information about how many times she chose each color of marble. Therefore, we assume that she chose each color of marble an equal number of times. Since there are three colors of marbles, this means that she chose each color 20 / 3 = 6 times.
Step 3: Calculate the experimental probability of choosing a blue marble
The experimental probability of an event is the number of times the event occurred divided by the total number of trials. In this case, the event is choosing a blue marble, and the total number of trials is 20. Therefore, the experimental probability of choosing a blue marble is 6 / 20 = 0.3.
Step 4: Convert the experimental probability to a percentage
To convert the experimental probability to a percentage, we multiply by 100%. Therefore, the experimental probability of choosing a blue marble is 0.3 * 100% = 30%.
The following question may be like this:
Marnie conducted an experiment using a bag of 12 marbles containing an equal number of blue, red, and green marbles. She randomly chose one marble, noted the color, and returned the marble to the bag. Marnie did this for a total of 20 trials. What was the experimental probability of choosing a blue marble from a bag?