McGraw Hill Glencoe Algebra 1, 2012
MH
McGraw Hill Glencoe Algebra 1, 2012 View details
8. Probability Distributions
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Exercise 1 Page 806

Practice makes perfect
a Let represent the number of uses of the GPS system by a random user. We want to find the probability that a randomly chosen user will have used the GPS more than times, which is the same as finding the probability that the value of our random variable is greater than
Before we start calculating let's look at the given table.
Uses Customers

Since represents the number of uses of a GPS, we can rewrite the first column using our random variable

Value of Customers
To find we need to find the number of customers that have used the GPS system more than times. Looking at the table we can tell that there is only one outcome where To find the probability, we will use the Probability Formula.
We are given that the car dealership surveyed of its customers with a GPS and we have found that the number of customers for whom is
The probability that a randomly chosen customer will have used the GPS system more than times is equal to which can also be written as
b This time we want to find the probability that a randomly chosen customer will have used the GPS system no more than times. This is the same as finding the probability that the value of our random variable is less than or equal to
Let's look at the table we made in Part A again.
Value of Customers
We will consider the first rows of our table only because the value of is less than or equal to in these rows. Our event is made up of more simple events, so this is a compound event. Since the events are mutually exclusive events, we can calculate by adding the probabilities that each event occurs.
We will calculate each probability using the Probability Formula. Probability of each event is equal to the number of customers that are related to the given event divided by the total number of customers which is
Value of Customers Probability Simplified
Now we can substitute in the values from the table into our equation for
The probability that a randomly chosen customer will have used the GPS system no more than times is equal to which can also be written as