Sampling and Bias Review

Sampling and Bias Review

Sampling Methods

• Convenience Sample (Readily Available Subjects)

• Simple Random Sample (Equal Chance of Selection)

• Systematic Sample (Random start, then every kth added to sample)

• Stratified Sample (Similar groups [strata] sample from each strata)

• Cluster Sample (Different groups [clusters] select randomly, sample everyone in cluster

Multiple Choice

A ___ is a small portion of the population used to gather data from.

• Systematic Sampling Method
• Sample
• Population
• Bias

Multiple Choice

A ___ is a large group that includes everything being studied.

• Sample
• Stratified Sampling Method
• Population
• Voluntary-Response

Multiple Choice

Why do we randomly select our samples?

• for control
• reduce bias
• so we don't get the same answers from everyone
• to eliminate confounding results

Multiple Choice

Identify the sampling design: SCPS wants to survey its employees.  They pick 4 schools from the county and survey every single employee in each of the 4 buildings.

• cluster
• volunteer
• systematic
• simple random

Multiple Choice

An SRS of 25 students is taken from each grade to form the sample.  This is what type of sampling design?

• Cluster
• SRS
• Stratified
• Multistage

Multiple Choice

Marianne wanted to know students' opinion on the new schedule at school. She places students' names in a container and randomly picks out 20 names. 

• Convenience Sampling
• Systematic Random Sampling
• Simple Random Sampling
• Volunteer response

Multiple Choice

Each student in the school is given a different number.  A student is randomly selected from the first 25. That student and every 25^th student thereafter are in the sample.  This is what type of sampling design?

• SRS
• Systematic
• Multistage
• Stratitfied

Multiple Choice

The teacher samples her class by selecting all students sitting at group 1 and group 5 in her classroom. This sampling technique is called?

• SRS

• Stratified

• Systematic

• Cluster

Bias

• Bias is the systematic tendency to favor one outcome over the other

• Voluntary Bias--subjects are self-selected for the sample

• Undercoverage--The sample is selected in such a way that it excludes and entire part of the population

• Non-Response Bias--Subjects choose to not respond or not enough responses are obtained from the population.

• Response--Leading or confusing wording of questions, or the interviewer or sensitivity of the questions causes you to lie.

Multiple Choice

Source of bias that occurs when you ask people who are EASY to ask

• Response Bias

• Convenience Sampling

• Nonresponse

• Voluntary Response

Multiple Choice

Source of bias in which some groups of populations are LEFT OUT of the selection process

• Response Bias

• Undercoverage

• Convenience Sampling

• Voluntary Response

Multiple Choice

Source of bias in which people CHOOSE to respond and usually only people with very strong opinions respond

• Response Bias

• Undercoverage

• Convenience Sampling

• Voluntary Response

Multiple Choice

“Some cell phone users have developed brain cancer. Should all cell phones come with a warning label explaining the danger of using cell phones?”

What kind of bias is evident in this survey question?

• Undercoverage Bias

• Non-Response Bias

• Response Bias

• Voluntary Response Bias

Multiple Choice

Many websites like Amazon and Yelp include customer ratings and reviews of products, restaurants, hotels, and so on. What is the predominant bias evident in these ratings and reviews?

• Response Bias

• Non-Response Bias

• Undercoverage Bias

• Voluntary Response Bias

Multiple Choice

I want a representative sample of likely voters. I use a telephone directory to randomly select 200 people. What is the most apparent bias?

• Undercoverage

• Nonresponse

• Response

• Voluntary Response

Multiple Choice

A nonsampling error occurs when someone gives an incorrect response to a sample survey. What is it called when a systematic pattern of incorrect responses occurs?

• nonresponse

• bias

• response bias

• undercoverage