7.SP.A.1-Sampling the Truth: Making Smart Inferences from Data

​Sampling the Truth: Making Smart Inferences from Data

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population

sample

expensive

time-consuming

difficult

population

Drag and Drop

In a survey, 1600 randomly selected U.S. adults are asked whether they have purchased a product online. The results are shown in the circle graph.

Identify the Population and Sample

Population = ​ ​

Placeholder

Sample = ​

Placeholder

Drag these tiles and drop them in the correct blank above

All U.S. Adults

The 1600 U.S. adults surveyed

The 81% of U.S. adults

The 19% of U.S. adults

Dropdown

What is the difference between a sample and a population?



A ​

Select answer

is a set of all items or events which are of interest for some question or experiment.

It is generally the group you are trying to make predictions or learn something about.

For most studies, it is either impossible or impractical to obtain data on an entire population.

This is why you need to use a smaller selection of items.

A ​

Select answer

is a selection of observations from a population. We measure data in a known sample to make a prediction, or inference, about the population.

Dropdown

What is the difference between a sample and a population?



A ​

Select answer

is a set of all items or events which are of interest for some question or experiment.

It is generally the group you are trying to make predictions or learn something about.

For most studies, it is either impossible or impractical to obtain data on an entire population.

This is why you need to use a smaller selection of items.

A ​

Select answer

is a selection of observations from a population. We measure data in a known sample to make a prediction, or inference, about the population.

representative

biased

biased

Multiple Choice

A school principal wants to know how teachers are liking the new rules she put in place. She surveys all the math and science teachers. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

A high school is going to have a party for their graduating seniors. They want to serve food that most of the seniors like. They pick 25 random names from a hat and survey those students. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

Casey surveyed the members of his soccer team to ask them what their favorite sport is. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

Green Valley Middle School conducted a survey of 125 random students asking them how much time they spend each night on homework. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

Shelley wants to survey grocery shoppers about their favorite brands. She goes to the store at 8am and surveys the first 50 people. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

A school district wants to know if parents would prefer to get phone calls or emails from the schools. They survey the parents of all the seventh grade students enrolled in the district. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased Sample

Multiple Choice

An airline wants to know if people prefer to check their luggage or carry it on. They ask every 10th person that walks into the airport. Is this a biased sample or unbiased sample?

• Biased Sample

• Unbiased sample?

Multiple Choice

Look at question. Pay close attention to highlights.

Which group of people should Lindsay and Justin survey to achieve the most accurate results?

• a

• b

• c

• d

Multiple Choice

Look at question. Pay close attention to highlights.

Which sample population will give the most accurate data?

• a

• b

• c

• d

Multiple Choice

Look at question. Pay close attention to highlights.

Which surveying method is the best option?

• a

• b

• c

• d

Multiple Choice

Look at question. Pay close attention to highlights.

Which method would provide the most valid results?

• a

• b

• c

• d

random

equal

bias

hat

random number

UNBIASED SAMPLES

To get valid results, a sample must be chosen very carefully. An unbiased sample is selected so that it accurately represents the entire population.

BIASED SAMPLES

In a biased sample, one or more parts of the population are favored over another. The results of a biased sampling method are invalid.

Let's Practice!

For the next several slides, determine whether each conclusion is valid by identifying the type of sampling method used for the survey.

Multiple Choice

To evaluate the defect rate of its memory chips, an integrated circuit manufacturer tests every 100th chip off the production line. Out of 10 chips tested, one chip is found to be defective. The manufacturer concludes that 3 chips out of 3,000 will be defective.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

Students who wish to represent the school at a school board meeting are asked to stop by the office after lunch. After lunch, 5 students wish to represent the school.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

To determine if the class understood the homework assignment, the math teacher checks the top 3 papers in the pile of collected homework. The teacher finds that all students understood the homework assignment.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

A member of the cafeteria staff asks every fifth student leaving the cafeteria to rank 5 vegetables from most favorite to least favorite. She finds that corn is one of the favorite vegetables.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

One bead for every member of the school orchestra is placed in a bag. All but 2 of the beads are white. Each member draws a bead from the bag, and the members who pick the non-white beads will represent the orchestra. It is predicted that two different instrument players will choose the white beads.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

A real estate agent surveys people about their housing preferences at an open house for a luxury townhouse. He finds that most people prefer townhomes.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

To determine the most popular children’s programs, a television station asks parents to call in and complete a phone survey. The television station finds that the children’s programs that are animated are the most popular.

• Valid - Simple Random Sample

• Valid - Systematic Random Sample

• Invalid - Convenience Sample

• Invalid - Voluntary Response Sample

Multiple Choice

Look at the image attached. Pay close attention to the highlighted text.

Which scenario would provide the least biased results?

• a

• b

• c

• d

Multiple Choice

Look at the image attached. Pay close attention to the highlighted text.

Which scenario would provide the least biased results?

• a

• b

• c

• d

inference

representative

invalid

Multiple Choice

Valid or Invalid

Should more money be put into athletic programs or music programs at school? Ask: students in the band program.

• Invalid

• Valid

Multiple Choice

Valid or Invalid

At her field hockey practice, Janet surveyed the athletes on the girls' hockey team to determine which sports teenagers like best. Will here sampling method be likely to produce valid or invalid results?

• Valid

• Invalid

Multiple Choice

valid or invalid

every tenth student on the roster was asked to come take a survey on the best sport the school offers.

• valid

• invalid

Multiple Choice

Valid or Invalid

Mr. Bowker wants to know how many students like sports so he randomly surveys 20 football players and 10 volleyball players. Of the 30 students surveyed, 100% like sports.

• Valid

• Invalid

Multiple Choice

Valid or Invalid

Jase wanted to see what everybody thinks about math. He asked everybody that was in the math club.

• Valid

• Invalid

Multiple Choice

valid or invalid

the soccer coach picked every 3rd kid to take a survey on their favorite sport.

• valid

• invalid

Multiple Choice

A researcher asked five of his doctor friends if they thought the new Brand X medicine that he developed was effective. Four responded "yes." The researcher used the results to write a TV advertisement claiming that "4 out of 5 doctors prefer Brand X medicine." Is this a valid inference? Explain.

• No, because the doctors asked are not a representative sample of the population of doctors.

• No, because 4 doctors said yes out of 9 who were asked.

• Yes, because the doctors asked are a representative sample of the population of doctors.

• Yes, because 4 doctors said yes out of the 5 who were asked.

Multiple Choice

Shantel and Syrus are researching what types of novels people prefer. They decide to survey people at the mall. Shantel uses systematic sampling and asks every seventh person at the entrance. She finds that 21% prefer romance novels. Syrus uses convenience sampling and asks every person in only one store. He finds that 48% prefer romance novels. Whose inference do you agree with?

• Shantel

• Syrus

Multiple Choice

Look at the image attached. Pay close attention to the highlighted text.

Is the survey sample a valid representation of the entire school, and why?

• a

• b

• c

• d

Multiple Choice

Look at the image attached. Pay close attention to the highlighted text.

Which survey option will give the cafeteria a valid result?

• a

• b

• c

• d

Multiple Choice

Look at the image attached. Pay close attention to the highlighted text.

Which sampling method could the company use so that valid inferences can be made regarding the results of the survey?

• a

• b

• c

• d

decisions

predictions

poor/inaccurate

Match

Match the following.

• The population being studied is...

• The sample being used is...

• The best math teacher is...

Students in the Volusia County School District.

The students that are interviewed for the study.

Mr. Siedell no question!

• Students in the Volusia County School District.

• The students that are interviewed for the study.

• Mr. Siedell no question!

Match

Match the following.

• The population is:

• The sample is:

• The best subject in school is:

The adults in Jacksonville, Florida.

The first person coming into the UNF library every 30 minutes.

Math

• The adults in Jacksonville, Florida.

• The first person coming into the UNF library every 30 minutes.

• Math

Match

Match the following

Systematic Sample

Simple Random Sample

Cluster Sample

Stratified Sample

• Systematic Sample

• Simple Random Sample

• Cluster Sample

• Stratified Sample

Match

Page 375 #2

• The Sample

• The Population

• Type of Sample

Every 10th smart phone

All smart phones the company produces

Systematic: pattern of every 10th phone

• Every 10th smart phone

• All smart phones the company produces

• Systematic: pattern of every 10th phone

Match

Match the following vocabulary

• a subset which you want to interview

• the bigger set where your subset came from

• random sample

• biased sample

• inference

sample

population

a fair sample. all are represented

does not represent subgroups in a population

using values from sample to predict for another group

• sample

• population

• a fair sample. all are represented

• does not represent subgroups in a population

• using values from sample to predict for another group

Match

Match the following terms with the correct situation.

• Biased Sample

• Sample

• Random Sample

• Population

• Convenient Sample

Sonya picked her family and friends to take a survey opting to add new items to the school menu.

Dr. Oatts surveyed Heritage's students about the dress code for the district.

Sheldon asked every 10th customer going in the movie theatre what type of movie they will watch.

Dr. Williams had the entire student body to participate in a poll.

Debra wanted to know if her paintings would sell, so she surveyed her peers in her Art class.

• Sonya picked her family and friends to take a survey opting to add new items to the school menu.

• Dr. Oatts surveyed Heritage's students about the dress code for the district.

• Sheldon asked every 10th customer going in the movie theatre what type of movie they will watch.

• Dr. Williams had the entire student body to participate in a poll.

• Debra wanted to know if her paintings would sell, so she surveyed her peers in her Art class.

Match

Juna is interested in determining if all surfers in Florida own a long board. He surveys a random sample of 54 Florida surfers to determine if they own a long board.

Match the answer to the question.

• The 54 surfers

• All Florida surfers

• Yes, its random, the sample and population is large.

Who is the sample?

Who is the population?

Will this pass the CLT?

• Who is the sample?

• Who is the population?

• Will this pass the CLT?

Multiple Choice

Miss Henderson wants to determine what her students enjoy most and least about her class. Which is the best way to collect this information from her students?

• List two of your favorite school subjects.
  List two school subjects that are difficult for you.

• List two of your favorite things about class.
  List two of your least favorite things about class.

• Mark any of the following that are your favorite things about class.
  homework
  tests
  quizzes
  activities
  reading time
  math
  social studies

• Mark any of the following that you earned a good grade in.
  homework
  tests
  quizzes
  activities

Multiple Choice

Which group would be best for Ryan to survey?

• a

• b

• c

• d

Multiple Choice

Which design should produce the most valid results?

• a

• b

• c

• d

Multiple Choice

Which of the following could the official do to help ensure that the sample is representative?

• a

• b

• c

• d

Multiple Choice

Which is the population?

• an entire deck of cards

• five heart cards

Match

Match the following ...

• Biased Sample

• Unbiased Sample

• Subject this assignment is from

Not valid - Unfair sample

Valid - fair random sample

Math

• Not valid - Unfair sample

• Valid - fair random sample

• Math

Dropdown

When a sample does not accurately represent the population it is a:​ ​

Select answer

Multiple Choice

The sample represents the population.

Choose the answer that says "Representative Sample"

• Random Sample

• Biased Sample

• Representative Sample