Unit 4: Collecting Data

Question 1

Population

Answer 1

The entire group of individuals that the information is supposed to represent.

Question 2

Sample

Answer 2

The subset of the population used to gather information.

Question 3

Sample Survey

Answer 3

A study that asks questions of a sample in the hope of learning about the entire population.

Question 4

Convenience Sample

Answer 4

Sampling in which individuals are chosen based on how easy they are to reach.

Question 5

Bias

Answer 5

Using a method that statistically favors certain outcomes.

Question 6

Voluntary Response Sample

Answer 6

Sampling in which individuals choose themselves by responding to a general appeal. Ex: A receipt’s survey at the bottom.

Question 7

Simple Random Sample (SRS)

Answer 7

Sampling in which each individual from a population has an equal chance of being in the selected sample via random picking.

Question 8

Stratified Random Sample

Answer 8

Sampling in which the population is divided into groups of individuals that have similar characteristics (called strata), then SRS is drawn from each stratum & combined to make the sample.

Question 9

Cluster Sample

Answer 9

Groups of individuals that mimic the characteristics of the entire population (called clusters).

Question 10

Systematic Sample

Answer 10

A sample in which individuals are chosen systematically from a sampling frame. The first number must be random. Ex: Every 10th person.

Question 11

Multi-Stage Sampling

Answer 11

Sampling in which you combine several different types of sampling methods.

Question 12

Inference

Answer 12

Drawing conclusions about a population based on the results from a sample.

Question 13

Margin of Error

Answer 13

How far we expect estimates to vary from the truth, at most.

Question 14

Sampling Errors

Answer 14

Errors that are the result of the sampling process.

Question 15

Sampling Frame

Answer 15

A list of individuals from which the sample is drawn.

Question 16

Undercoverage

Answer 16

The inability to be able to represent the entire population due to certain groups being unable to be represented. Ex: Sampling via phone numbers excludes people that do not own phones.

Question 17

Nonsampling Errors

Answer 17

Errors that result after the sample is selected.

Question 18

Nonresponse

Answer 18

An individual chosen for a sample can’t be contacted or refuses to participate.

Question 19

Response Bias

Answer 19

A systematic pattern of incorrect responses in a sample survey. Similar to Desirability Bias.

Question 20

Observational Study

Answer 20

A study in which members of a survey are surveyed without being affected in any way.

Question 21

Experiment

Answer 21

A controlled study conducted to test a hypothesis by manipulating one or more independent variables and observing the effects on one or more dependent variables.

Question 22

Lurking Variable

Answer 22

Variables that are not among the explanatory or response variables in a study but may influence the response variable.

Question 23

Confounding

Answer 23

Refers to two variables that are associated in such a way that effects on a response variable cannot be distinguished from each other.

Question 24

Treatments

Answer 24

A specific condition applied to individuals in an experiment.

Question 25

Experimental Units

Answer 25

Smallest collection of individuals to which treatments are applied.

Question 26

Subjects

Answer 26

When the experimental units are people, they are referred to as subjects.

Question 27

Factors

Answer 27

Explanatory variables in an experiment

Question 28

Levels

Answer 28

The specific values of each of the factors.

Question 29

Random Assignment

Answer 29

Experimental units that are assigned to treatment groups at random.

Question 30

Completely Randomized Design

Answer 30

Treatments are assigned to all experimental units completely by chance.

Question 31

Control

Answer 31

To ensure that the only systematic difference between treatment groups is the treatment itself.

Question 32

Replication

Answer 32

Refers to using enough experimental units so that differences in the effect of the treatments can be distinguished from chance differences between the groups.

Question 33

Placebo Effect

Answer 33

The response to a dummy/fake treatment.

Question 34

Single Blind Experiment

Answer 34

An experiment in which only the subject doesn't know which treatment they received OR the subject knows but not the response variable.

Question 35

Double Blind Experiment

Answer 35

An experiment in which neither the subject nor the experimenter know what group/treatment they're receiving.

Question 36

Statistically Significant

Answer 36

If the results from an experiment are statistically significant, it means that an observed effect is so large that is would rarely occur by chance.

Question 37

Randomized Block Selection

Answer 37

A group of similar experimental units, similar to stratified sampling.

Question 38

Matched Pairs

Answer 38

Compares two treatments by matching pairs of similar experimental units. Often times, this is accomplished by testing two treatments on the same subjects.