Question

Difficulty: HardExperimental and Theoretical Probability

A bag contains 55 red balls, 33 blue balls, and nn green balls. The theoretical probability of drawing a blue ball at random from the bag is 320\frac{3}{20}. In a probability experiment, a ball is drawn at random from the bag and replaced 500500 times. If a green ball is observed 340340 times, calculate the absolute difference between the experimental probability and the theoretical probability of drawing a green ball.

Answer: 0.08

Answer

The absolute difference between the experimental probability and the theoretical probability of drawing a green ball is 0.080.08 (or 225\frac{2}{25}).
The theoretical probability of drawing a blue ball establishes that the bag contains 2020 total balls, meaning there are 1212 green balls. The theoretical probability of picking a green ball is therefore 1220=0.60\frac{12}{20} = 0.60. The experimental probability is 340500=0.68\frac{340}{500} = 0.68. Taking the positive difference gives 0.680.60=0.08|0.68 - 0.60| = 0.08.

Step-by-Step Solution

1
Find the total number of balls and the value of nn
n=12n = 12, Total balls = 2020
The theoretical probability of picking a blue ball is 38+n=320\frac{3}{8+n} = \frac{3}{20}, giving 8+n=208 + n = 20.
2
Find the theoretical probability of drawing a green ball
P(Green)theo=0.60P(\text{Green})_{\text{theo}} = 0.60
There are 1212 green balls out of 2020 total balls, so 1220=0.60\frac{12}{20} = 0.60.
3
Find the experimental probability of drawing a green ball
P(Green)exp=0.68P(\text{Green})_{\text{exp}} = 0.68
In 500500 trials, a green ball was observed 340340 times, so 340500=0.68\frac{340}{500} = 0.68.
4
Calculate the absolute difference
0.680.60=0.08|0.68 - 0.60| = 0.08
Subtract the theoretical probability from the experimental probability and take the absolute value.

Key Concept

Comparison of theoretical probability based on outcome sample space and experimental probability based on observed trial relative frequencies.
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