Unit 4

Question 1

the entire group of individuals we
want information about.

Answer 1

population

Question 2

This collects data from every individual in the population.

Answer 2

census

Question 3

a subset of individuals in the population from which we
actually collect data.

Answer 3

sample

Question 4

a study that collects data from a sample that is chosen
to represent a specific population.

Answer 4

sample survey

Question 5

The design of a statistical study shows
bias if

Answer 5

it is very likely to under or over estimate the value you want to know.

Question 6

convenience sampling is a bad way to sample because

Answer 6

it will almost always result in bias.

Question 7

this is a method of sampling whereby you are Choosing individuals from the
population who are easy to reach

Answer 7

convenience sampling

Question 8

this allows people to choose to be
in the sample by responding to a general invitation.

Answer 8

voluntary response sampling

Question 9

why is voluntary response sampling a bad way to sample?

Answer 9

People who
self-select to participate in such surveys are usually not
representative of some larger population of interest.

Question 10

involves using a chance
process to determine which members of a
population are included in the sample.

Answer 10

Random sampling

Question 11

A —- of size ‘n’ is
chosen in such a way that every group of ‘n’
individuals in the population has an equal
chance to be selected as the sample.

Answer 11

simple random sample (SRS)

Question 12

When choosing an SRS:

Answer 12

Label, Randomise, Select.

Question 13

— are groups of individuals in a population who share characteristics
thought to be associated with the variables being measured in a study.

Answer 13

Strata

Question 14

—- selects a sample by choosing an SRS from each stratum and combining the SRSs into one overall sample.

Answer 14

Stratified random sample

Question 15

Stratified random sampling works best when the individuals within each
stratum are

Answer 15

similar.

Question 16

When populations are large and spread out over a wide area, we’d prefer
a method called

Answer 16

cluster sampling.

Question 17

A —- is a group of individuals in the population that are located near
each other.

Answer 17

cluster

Question 18

Cluster sampling works best when

Answer 18

the clusters look just like the population but on a smaller scale.

Question 19

The main reason for using cluster sampling is

Answer 19

for practical reasons, like saving time and money.

Question 20

Undercoverage occurs when

Answer 20

members of the population are less
likely to be chosen or cannot be chosen in a sample.

Question 21

Nonresponse occurs when

Answer 21

an individual chosen for the sample can’t be contacted or refuses to participate.

Question 22

Response bias occurs when

Answer 22

there is a systematic pattern of inaccurate answers to a survey question.

Question 23

observes individuals and measures
variables of interest but does not attempt to influence the responses.

Answer 23

Observational study

Question 24

measures an outcome of a study.

Answer 24

response variable

Question 25

may help explain or predict changes in a response variable

Answer 25

explanatory variable

Question 26

Confounding occurs when

Answer 26

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

Question 27

An --- deliberately imposes some treatment on individuals to measure their responses.

Answer 27

experiment

Question 28

What is the MAIN difference between an experiment and an observational study?

Answer 28

An experiment administers treatment while an observational study does not.

Question 29

a treatment that has no active ingredient, but is otherwise like other treatments.

Answer 29

Placebo

Question 30

A specific condition applied to the individuals in an experiment is called a

Answer 30

treatment

Question 31

the object to which a treatment is randomly assigned.

Answer 31

experimental unit

Question 32

If an experimental unit is a human, it is often called a

Answer 32

subject

Question 33

a variable that is manipulated and may cause a change in the response variable.

Answer 33

factor

Question 34

The different values of a factor are called

Answer 34

levels

Question 35

a --- is used to provide a baseline for comparing the effects of other treatments.

Answer 35

control group

Question 36

The --- describes the fact that some subjects in an experiment will respond favorably to any treatment, even an inactive treatment.

Answer 36

placebo effect

Question 37

In a ------ experiment, neither the subjects nor those who interact with them and measure the response variable know which treatment a subject received.

Answer 37

double blind

Question 38

In a ---- experiment, either the subjects don’t know which treatment they are receiving or the people who interact with them and measure the response variable don’t know which subjects are receiving which treatment.

Answer 38

single blind

Question 39

To create roughly equivalent groups at the beginning of an experiment, we use

Answer 39

random assignment

Question 40

In an experiment, control means

Answer 40

keeping other variables constant for all experimental units.

Question 41

In an experiment, replication means

Answer 41

using enough experimental units to distinguish a difference in the effects of the treatments

Question 42

What are the four principles of Experimental design?

Answer 42

Comparison, Random assignment, Control, Replication

Question 43

In a completely randomized design, the experimental units are assigned to the treatments completely

Answer 43

by chance.

Question 44

a group of experimental units that are known before the experiment to be similar in some way that is expected to affect the response to the treatments.

Answer 44

block

Question 45

the random assignment of experimental units to treatments is carried out separately within each block.

Answer 45

randomized block design

Question 46

a common experimental design for comparing two treatments that uses blocks of size 2. In some designs, two very similar experimental units are paired and the two treatments are randomly assigned within each pair. In others, each experimental unit receives both treatments in a random order.

Answer 46

matched pairs