Mr. Spence Algebra Hsa Sampling Method Type Questions

Front 1

Apples from an orchard need to be sampled to see if they are sweet enough for juice. The orchard has 25,000 apple trees. Each tree has at least 1,000 apples.

Alfred suggests, “Randomly choose one tree and test 500 apples from that tree.”

Betsy suggests, “Randomly choose 1,000 trees and test one apple from each tree.”

Which person has the better method and why?

Back 1

Betsy does. She is using an unbiased method called stratified random sampling because all of the apples might be picked.

Alfred's method is a convenient sampling method. It's easy to pick just one tree, but all of the other trees are being under-represented.

Front 2

Systematic Random Sampling

Back 2

When a sample is chosen by choosing every nth item or using a time interval. (ex: selecting every 10th coke can. OR selecting a person every 20 seconds).

Front 3

The Knitwear Company wants to know what sock colors teenagers will buy. The company is considering the three options below for collecting data.

Option 1: Spend five days in the sock department of a randomly selected store and ask every person who enters what color socks they buy.

Option 2: Spend one day in the sock departments of five randomly selected stores in randomly selected cities and ask every teenager who enters what color socks they buy.

Option 3: Spend one day in eight randomly selected shopping centers and ask ten randomly selected teenagers at each shopping center what color socks they buy.

Which option gives the most represented sample?

Back 3

Option 3: It gives the widest range of stores and teenagers in the scenario.

Front 4

Stratified Random Sampling

Back 4

When a sample is chosen by dividing the population in a fair way, then randomly choosing the same number of items in each divided section. (ex: separating a high school by boys and girls, then selecting 50 boys and 50 girls randomly).

Front 5

The principal will survey 100 students to determine which elective courses to offer next year. The principal will use one of the methods below.

Method A: Survey the first 100 students who enter the cafeteria on a randomly selected day.

Method B: Have 25 teachers each randomly select 4 eleventh-grade students to be surveyed.

Method C: Assign each student a number. Use a random number generator to generate 100 numbers. Survey those students whose numbers are generated.

Which method uses the principles of Simple Random Sampling the best?

Back 5

Method C, because everyone has an equally likely chance of being picked.

Method A is a biased method, because it's easy or CONVENIENT.

Method B is only focused on 11th graders which is a biased method, since 9th, 10th and 12th graders are being under-represented.

Front 6

Simple Random Sample

Back 6

The fairest type of sampling method. Everyone and everything has an equally likely chance of being chosen. (ex: drawing a name out of a hat).

Front 7

Inés wants to conduct a survey to determine how many customers see the advertisement for her store. Which of these methods provides Inés with the most representative sample of her customers

A. Survey customers who live near her store.
B. Survey customers who shop at her store on weekends.
C. Survey customers who shop at her store early in the morning.
D. Survey customers who shop at her store at different times throughout the week.

Back 7

D. This will provide the greatest representation.

Can't be A because what about the people who live far away from the store.

Can't be B. What about the people who don't shop on the weekends.

Can't be C: What about the shoppers that shop in the middle of the day or night? It's not fair.

Front 8

Convenient Sampling Method

Back 8

When you chose a sample because it's "easy." (ex: Choosing the first 10 papers in a stack. Picking the first 10 people that walk through the door. Choosing your friends to fill out a survey.

Front 9

A teacher conducts a random survey to determine how many students use the school library on a regular basis. Which of these methods would provide the teacher with a simple random sample?

A. Choose every 3rd student that enters the library on Monday.
B. Select 50 students from the list of students who have perfect attendance.
C. Choose the name of every 10th student in her grade book until 30 names are selected.
D. Number every student in the school and then generate random numbers to select 50 students.

Back 9

Answer D because everyone has an equally likely chance.

Can't be A: Systematic
Can't be B: Convenient
Can't be C: Systematic

Front 10

Voluntary Sampling Method

Back 10

A person chooses to be a part of the sample. (ex: You call in to vote for "American Idol." You put a suggestion box at the store and if someone wants to fill it out they can.

Front 11

Biased Sampling Methods

Back 11

The two types are Voluntary and Convenient. Biased sampling methods are "unfair" in some way.

Front 12

Unbiased Sampling Methods

Back 12

The three "S's." Simple Random, Systematic and Stratified. These are fair ways of getting a sample.

Front 13

Sample

Back 13

A sample is a part of the population. You get samples so that you can make predictions of the entire population. (ex: a gallon of water from a pool. 50 people from your church).

Front 14

Population

Back 14

The entire thing you are testing. (ex: Everyone in a high school. All of the water in the pool).

Front 15

What is the sampling method?

You pick every 4th person that walks through the door.

Back 15

Systematic: Every 4th makes it systematic.

Front 16

What is the sampling method?

You take the top 20 papers in a stack to review.

Back 16

Convenient: It's easy to do this.

Under-represented: All of the other papers in the stack.

Front 17

What is the sampling method?

The grocery store manager puts a suggestion box at the door.

Back 17

Voluntary:

Under-represented: Anyone that doesn't fill out a suggestion.

Front 18

What is the sampling method?

You split the school into BOYS/GIRLS and then randomly pick 50 from each.

Back 18

Stratified: Divide the population into parts, then randomly select a certain number from each part.

Front 19

What is the sampling method?

You put everyone's name in a hat and select 50 kids.

Back 19

Simple Random Sample: Because everyone is being represented.

Front 20

John is doing a survey and asks 20 of his friends to fill it out. Is this biased? unbiased? and Why?

Back 20

It is biased because it's an example of a convenient sample. All people that aren't his friends are being under-represented.

Front 21

What is the sampling method?

You randomly select one person's name from each page of the phone book.

Back 21

Stratified Random Sample: You dividing the phone book by pages and then randomly selecting one person per page.

Front 22

What is the sampling method?

You walk down each row of your corn field and randomly select a corn cob every 40 seconds.

Back 22

Systematic. The "every 40" seconds is the key piece for deciding systematic.

Front 23

What is the sampling method?

You call in to vote for the top song for your radio station you listen to.

Back 23

Voluntary:

Under-represented: All the people that don't call in.

Front 24

Is the following biased or not biased?

Janet wants to select kids in her classroom to answer questions, so she puts all her students in a Random Generator that she uses on her computer.

Back 24

Unbiased because everyone has a chance of being picked.