8th Grade Math Test, Mod 9

People aged 16-25 are asked whether or not they have a driver's license. The results are shown in the table.

What question can best be answered by the table?

• What percentage of people between 16-20 have a driver's license?

• Are people aged 21-25 more likely to have a driver's license than people aged 16-20?

• Are people aged 21-25 more likely to have a driver's license than people aged 26-30?

• What percentage of people aged 16-25 don't have a driver's license?

Answer explanation

Since this is sample data, we can best compare the two groups relative to each other, while we can only make inferences about the larger populations.

People aged 16-25 are asked whether or not they have a driver's license. The results are shown in the table.

What is the conditional relative frequency of having a driver's license given that the person is aged 16-20? (Round to the nearest hundredth)

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Answer explanation

Customers at an ice cream shop are asked if they want sprinkles or caramel on their ice cream. The results are shown in the table. Which statement is supported by the results?

• More customers want sprinkles than caramel.

• Fewer customers want caramel than want no caramel.

• More customers want caramel and no sprinkles than no caramel.

• Fewer customers want sprinkles and caramel than want sprinkles and no caramel

Answer explanation

Customers that wanted caramel and no sprinkles: 40

Customers that wanted no caramel: 31

Customers at an ice cream shop are asked if they want sprinkles or caramel on their ice cream. What

What percentage of people surveyed wanted both caramel and sprinkles on their ice cream?

• 28%

• 50%

• 78%

• 64%

Answer explanation

Some middle school students are asked if they play football or soccer.

The results of the survey are shown in the table.

True or False:

Approximately 12% of students that don't play football also don't play soccer.

• True
• False

Answer explanation

Some middle school students are asked if they play football or soccer.

The results of the survey are shown in the table.

What is the marginal relative frequency of students that don't play football (rounded to the nearest hundredth)?

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Answer explanation

Students in a classroom recorded if they were right or left-handed as well as if they had or didn't have blue eyes.

The results of the survey are shown in the relative frequency table.

What is the joint relative frequency that a student is right handed and doesn't have blue eyes?

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Answer explanation

Since the table is already in relative frequencies, the answer is 0.61.

Students in a classroom recorded if they were right or left-handed as well as if they had or didn't have blue eyes.

The results of the survey are shown in the relative frequency table.

True or False:

Approximately 5% of students are left-handed and have blue eyes.

• True
• False

Answer explanation

This is joint relative frequency, so if a student has both of these features, the frequency is the intersection between them.

Mrs. Smith recorded whether each of her students attended her class yesterday as well as if they passed last exam. However, she wrote it down in pen, which got smudged!

How many students attended class in total?

Answer explanation

First, find how many students passed and did not attend class, 2. Then how many students did not attend class in total, 8. Then subtract that from the total amount of students to get 30.

Mrs. Smith recorded whether each of her students attended her class yesterday as well as if they passed last exam.

Is there an association between attending class and passing the exam? Why or why not?

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Answer explanation

You can make a really good argument that there is an association. This is because 75% of students who did not attend failed the exam.