Envision Math 2.0: Grade 7, Volume 2
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Exercise 1 Page 328

Practice makes perfect
We know that Sunil is the ticket manager at a local soccer field and wants to conduct a survey to find the answer to the following question.

How many games do most spectators attend during the soccer season?

First let's determine the population for Sunil's survey. Remember that a population is an entire group of people from which data can be collected. In Sunil's study, the population is all spectators that attend games at a soccer field where Sunil works. Now, we want to think how Sunil could collect a representative sample of this population.

Representative Sample

A sample that has the same characteristics as the population.

There are some ways in which we can determine a representative sample. The most reliable way is to generate a random sample. For example, Sunil could assign each ticket a different integer and then draw some numbers randomly. People with ticket numbers Sunil drew could be then surveyed.

Let's take a look at a table with the results Sunil obtained after conducting the survey.
Soccer Game Attendance
Number of Games Number of Spectators
1-2 57
3-4 43
5 or more 50

Based on the results from the survey, Sunil can infer that most spectators attend 1 or 2 games during the soccer season.

Now, we want to use the survey data to estimate the number of spectators n who attended 5 or more games this season if 2400 spectators attend at least 1 game this soccer season. Before we do that, let's take a look at the results of Sunil's survey and highlight the number of spectators in a sample that attended at least 5 games.

Soccer Game Attendance
Number of Games Number of Spectators
1-2 57
3-4 43
5 or more 50
The total number of survey participants is 57+43+50= 150. Now, the proportion of spectators who attend 5 or more games per season in Sunil's representative sample should be about the same as the proportion of spectators who attend 5 or more games this season. This means we can write the following equation. 50/150= n/2400 Let's solve the proportion for n.
50/150=n/2400
50/150* 2400=n/2400*2400
50/150* 2400 =n
120 000/150=n
800=n
b=800
Based on the sample, Sunil can expect about 800 spectators to attend 5 or more games this season.