Topic 6 - Use Sampling to Draw Inferences About Populations

A theme park has many attractions, one of which is the roller coaster. Are the people who ride the roller coaster the population or a sample of the theme park? Explain.

• Sample. They are a subset of all the people at the theme park.

• Population. They are all the people at the theme park.

"Lana and Jeff each randomly surveyed 15 students about their favorite types of movies." What is the key word that shows that these samples are representative (good samples) of the school population?

• randomly

• survey

• favorite

• 15 students

The principal at Marina Middle School wants to determine if the 120 students in the seventh grade prefer to visit the aquarium or the science museum for their end-of-year trip. Select all the sets of people that would be a representative (good) sample of the population. (Hint: 2 answers)

• 20 sixth-grade students, 20 seventh-grade students, and 20 eighth-grade students

• 10 seventh-grade boys and 10 seventh-grade girls

• 25 seventh-grade students

• 15 seventh-grade boys and 5 teachers

• 25 students from the school

The Longboat Key town council wants to know if residents are in favor of a traffic camera at the main intersection in town. Match each term to the example it best describes.

Drivers who reside in Longboat Key = ​​ (a)  

Residents of Longboar Key = ​ (b)  

Residents randomly chosen from the town register = ​ (c)  

• NOT a representative sample
• Population
• Representative Sample

Students in Mrs. Walsh’s math class wanted to know the favorite snacks of students in the school. How could they generate a random sample to survey?

• The class could obtain an alphabetized list of all of the students in the school and select every seventh student.

• The class could each ask one of their best friends.

• The teacher can choose a sample of students.

• The class could select the first 20 students that visit the school canteen shop.

The food service manager conducted a random survey of students to determine their preference for new lunch menu items. Select all the inferences that can be drawn from the manager’s data. (Hint: There are 3 answers)

• About twice as many students prefer salad bar as compared to pita sandwiches.

• Burritos are the most preferred item.

• About three-fourths of students prefer

  either salad bar or burritos.

• Twice as many students prefer pizza as compared to pita sandwiches.

• About half as many students prefer pita sandwiches as compared to burritos.

Margo wants to convince her father to change her curfew from 9 P.M. to 10 P.M. She gathers data on curfew times from a random sample of students at her middle school. Can Margo use these data to present a valid inference that will convince her father? Explain.

• No. Most students have a curfew of 9 P.M. or earlier.

• Yes. Most students have a curfew of 10 P.M. or earlier.

• Yes. Some students have a curfew of 10 P.M. or later.

Russell randomly surveys seventh-graders in his school and finds that 6 of 30 attend summer camp. If there are 200 seventh-graders in his school, about how many are expected to attend summer camp?

Mathematical Equivalence

ON

Group A and Group B were randomly sampled from the same population. What inferences can you make?​

Group B has a higher ​ (a)   and less overall ​ (b)   (​ (c)   range) than Group A.

• median
• variability
• smaller
• bigger
• IQR

A random survey of seventh- and eighth-grade students was conducted to find out how many hours is spent doing homework each night. Of the two sets of data, which has the greater median?

• Seventh graders

• Eighth graders

• They are both the same.