McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Simulations
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Exercise 2 Page 911

Follow the steps for designing a simulation using random number generators.

See solution.

Practice makes perfect

We are given a table that shows the percent of members participating in 4 classes offered at a gym. We want to design and conduct a simulation to estimate the probability that a new gym member will take each class. First let's review the steps for designing a simulation.

  1. State each possible outcome and the corresponding theoretical probability.
  2. Determine if there are any assumptions.
  3. Choose and describe an appropriate probability model for the situation.
  4. Define a trial for the situation and choose the number of trials to be conducted.

We will follow these steps, then conduct the simulation, and report the results.

Designing a Simulation

Since we are interested in the probability that a new member will take each of 4 classes, we have 4 possible outcomes. Based on the given information, we will assume that the theoretical probability that a new gym member will take each class is the same as the given percentages.
Possible Outcomes Theoretical Probability Written as Fraction
Tae kwon do 45 % 9/20
Yoga 30 % 6/20
Swimming 15 % 3/20
Kick-boxing 10 % 2/20

Let's use a random number generator to perform the simulation. To do this, because we expressed the probabilities as fractions with denominators of 20, we will assign the integers from 1 to 20 to represent the probability data. Tae kwon do:& 1,2,3,4,5,6,7,8,9 Yoga:& 10,11,12,13,14,15 Swimming:& 16,17,18 Kick-boxing: & 19,20 Each trial — one generated number — will represent the choice of a new gym member. Let's choose the number of trials to be 20.

Conducting and Summarizing Data from a Simulation

We will use the random number generator in our graphing calculator. To do so, push the MATH button. Then scroll left to the PRB menu and choose the fifth option, randInt(.

After choosing this option, enter the minimum and maximum values of the set, and the number of trials. Next, push ENTER.

Now, we can make a frequency table to show the example results of our simulation. Remember the numbers that we assigned to represent each class when keeping track of the outcomes.

Outcome Tally Frequency
Tae kwon do |||| |||| 10
Yoga |||| | 6
Swimming ||| 3
Kick-boxing | 1
Total - 20

Using the results from the table, we can calculate the experimental probability P of choosing each class. We will divide the frequency of choosing each class by the number of trials, 20.

Outcome Frequency Probability P
Tae kwon do 10 10/20 or 50 %
Yoga 6 6/20 or 30 %
Swimming 3 3/20 or 15 %
Kick-boxing 1 1/20 or 5 %

Finally, we can create a bar graph showing these results.