AP Statistics: Sampling Methods Review

Example of Convenience sample

A statistics student interviews everyone in his apartment building to determine who owns a cell phone.

Voluntary Sampling

The researcher invites members of the population to participate in the survey on a voluntary basis.

Cluster sampling

the population is divided into heterogenous clusters and random selection is made within the clusters, or the entire cluster is used.

Example of multistage sampling

A class consists of 36 students seated in six different rows, with six students in each row, then rolls the die again to select a particular student in the row. This process is repeated until a sample of 6 students is obtained.

Example of Systematic sampling

Every fifth adult entering an airport is checked for extra security screening.

Example of Simple Random sample

The names of 100 employees are written on 100 cards. the cards are placed in a bag and three names are picked from the bag.

Example of Voluntary Sampling

A TV show host asks his viewers to visit his website and respond to an online poll.

Convenience Sample (Bias)

the individuals in the sample are easily obtained

A manager associated each employee's name with a number on one ball in a container, then drew balls without looking to select a sample of 555 employees. A.Simple Random Sample B. Stratified Sample C. Cluster Sample D.Systematic Sampling E. None of the above

A. It is simple random sample since each member receives a number first.

Example of Stratified sampling

Families were grouped according to their structure. Nuclear, Blended & Sole-parent families. From these groups, every second group took part in the research.

In order to survey the opinions of its customers, a restaurant chain obtained a random sample of 30 customers from each restaurant in the chain. Each selected customer was asked to fill out a survey. Which one of the following sampling plans was used in this survey? A. Cluster Sampling B. Stratified Sampling C. Systematic Sampling D. Simple Random Sampling E. Convenience Sampling

B Since the customers we divided by chain first then they are stratified.

A school chooses 33 randomly selected athletes from each of its sports teams to participate in a survey about athletics at the school. A. Simple Random Sample B. Stratified Sample C. Cluster Sample D. Systematic Sampling E. Convenience Sampling

B. Since they are breaking up the athletes into teams then it is stratified by teams to choose the sample.

A principal orders t-shirts and wants to check some of them to make sure they were printed properly. She randomly selects 2 of the 10 boxes of shirts and checks every shirt in those 2 boxes. A. Simple Random Sample B. Stratified Sample C. Cluster Sample D. Systematic Sampling E. Convenience Sampling

C. Since she is choosing 2 boxes but sampling all the shirts in those boxes

A politician asks his neighbors their opinions about a controversial issue. A. Simple Random Sample B. Stratified Sample C. Cluster Sample D. Systematic Sampling E. Convenience Sampling

E. Since he asks the people around him then he is conveniently asking his sample

A restaurant leaves comment cards on all of its tables to learn about customer satisfaction. Each comment card is a brief survey that customers can fill out if they choose to. A. Simple Random Sample B. Stratified Sample C. Cluster Sample D. Systematic Sampling E. Convenience Sampling

E. The restaurant is conveniently leaving the comment cards at the table.

Systematic Sample

Obtained by selecting every 10th (or 15th etc..) individual from the population

Stratified sampling

The population being used is divided into groups characterized by a common trait and then the sample has a representation of each group in the sample. For example, ensuring that various age brackets, genders, backgrounds and religions are used in the research.

Simple Random Sample

each individual in a population has an equally likely chance of being chosen

multistage sampling

select from successively smaller groups within the population in stages

Example of Cluster sampling

selecting a specific area to learn more about education. Each school in this area would be an example of this sample method