Unit 3 test

Question 1

What is an experiment?

Answer 1

Different conditions (treatments) are imposed upon subjects

Question 2

What may help to predict a change in the response variable?

Answer 2

Explanatory Variable

Question 3

What is used to measure the outcome of a study?

Answer 3

Response Variable

Question 4

Simple Random Sampling

Answer 4

Every group of a given size has an equal chance of being chosen

Question 5

Advantages of SRS

Answer 5

Unbiased, easy to explain

Question 6

Disadvantages of SRS

Answer 6

In certain cases, it can be difficult to implement and it may not be as precise as other methods

Question 7

Advantages of Cluster Random Sampling

Answer 7

Unbiased and easy to perform, practical and affordable

Question 8

Ideal situation for Cluster Sampling

Answer 8

You want it to be heterogeneous within groups, groups are similar to each other

Question 9

Stratified Random Sampling

Answer 9

population is divided into strata, based on a similar characteristic. SRS within each stratum is taken. Selected individuals are combined into larger samples.

Question 10

Advantages of Stratified Sampling

Answer 10

It represents the population by drawing some from each layer, reducing variability in the results that could arise because of differences among layers.

Question 11

Bias

Answer 11

Systematic tendency to favour certain responses over others.

Question 12

Examples of Selection/ Sampling Bias

Answer 12

Response Bias

Question 13

Examples of Survey Bias

Answer 13

Voluntary Response Bias, Nonresponse Bias, Convenience Sampling, Undercoverage Bias,

Question 14

What is Voluntary Response Bias?

Answer 14

When a sample is comprised entirely of volunteers or people who choose to participate.

Question 15

Why is Voluntary Response Bias is bad?

Answer 15

Asking people to be part of a sample will usually attract people with strong opinions, detract people who either don’t care or have something to hide which no longer accurately reflects the truth of the overall population.

Question 16

What is Convenience Bias?

Answer 16

One that is selected quickly out of ease for the researcher.

Question 17

Why is Convenience Sampling bad?

Answer 17

These types of samples introduce potential for bias because they do not use chance to select individuals.

Question 18

What is Undercoverage Bias?

Answer 18

Certain groups were excluded from the sample and when part of the population has a reduced chance.

Question 19

What is Response Bias?

Answer 19

Any problem in the data collection process that would result in data that is untruthful or incorrect.

Question 20

What is Non-response Bias?

Answer 20

Individuals chosen from the sample for whom data cannot be obtained and may differ from those for whom data can be obtained.

Question 21

Factor

Answer 21

The explanatory variable to be manipulated

Question 22

Levels

Answer 22

various settings for a factor (specific values experimenter chooses for factor)

Question 23

Treatment

Answer 23

Actual Assignments given to subjects

Question 24

Experimental Units

Answer 24

The “unit” receiving the assigned treatment and the “unit” measured at the end.

Question 25

Subjects

Answer 25

If experimental units are human

Question 26

Retrospective

Answer 26

Historical Data

Question 27

Benefits of Random Assignment

Answer 27

Helps to balance the effects of uncontrolled variables so that the differences in responses can be attributed to the treatment and nothing else.

Question 28

Benefits of Blocking

Answer 28

By blocking, we isolate the variability attributable to the difference between blocks so that we can see the difference caused by treatments more closely.

Question 29

Statistically Significant

Answer 29

A difference in the response variable so large that it cannot be attributed to natural sampling variability

Question 30

Purpose of Control Group

Answer 30

Assigned to a baseline treatment level, typically either default treatment (provides a basis for comparison).