Ch. 4 test

Question 1

The (blank) in a statistical study is the entire group of individuals we want information about. For example, all registered voters in a given county.

Answer 1

population

Question 2

A (blank) is a subset of individuals in the population from which we actually collect data.

Answer 2

sample

Question 3

A (blank) collects data from every individual in the population.

Answer 3

census

Question 4

The design of a (blank) shows bias if it would consistently underestimate or consistently overestimate the value you want to know.

Answer 4

statistical study

Question 5

A sample that chooses the individuals easiest to reach. This will typically result in a
biased sample of like-minded individuals.

Answer 5

convenience sample

Question 6

A sample that consists of people who choose themselves by responding to a general invitation. shows bias because people with strong opinions (often in the same direction) are most likely to respond.

Answer 6

Voluntary response samples

Question 7

A (blank) sample of size n consists of n individuals from the population chosen
in such a way that every set of n individuals has an equal chance to be the sample actually
selected.

Answer 7

simple random sample (SRS)

Question 8

A table of (blank) is a long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 with these two properties:

1. Each entry in the table is equally likely to be any of the 10 digits 0 through 9.
2. The entries are independent of each other. That is, knowledge of one part of the table
   gives no information about any other part.

Answer 8

random digits

Question 9

choose an SRS in two steps:

Answer 9

Step 1: Label. Assign a numerical label to every individual in the population.
Step 2: Table. Use Table B to select labels at random.

Question 10

To get a stratified random sample, start by…

Answer 10

1) Classifying the population into groups of similar
individuals, called strata.

2) Then choose a separate SRS in each stratum and combine these SRSs to form the sample.

Question 11

To get a cluster sample, start by…

Answer 11

1) Classifying the population into groups of individuals that are
located near each other, called clusters.

2) Then choose an SRS of the clusters. All individuals in the chosen clusters are included in the sample.

Question 11

(Blank) occurs when some members of the population cannot be chosen in a sample.

Answer 11

Undercoverage

Question 11

(blank) occurs when an individual chosen for the sample can’t be contacted or refuses to participate.

Answer 11

Nonresponse

Question 12

A systematic pattern of incorrect responses in a sample survey leads to (blank).

Answer 12

Response bias

Question 13

The (blank) is the most important influence on the answers given to a sample survey.

Answer 13

wording of questions

Question 14

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

Answer 14

observational study

Question 15

An (blank) deliberately imposes some treatment on individuals to measure their responses.

Answer 15

experiment

Question 16

(Blank) occurs when two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other. Observational studies often fail to provide valid causal links between variables due to confounding

Answer 16

Confounding

Question 17

A specific condition applied to the individuals in an experiment is called a (blank). If an experiment has several explanatory variables, a (blank) is a combination of specific values of these variables.

Answer 17

Treatment

Question 18

The (blank) are the smallest collection of individuals to which treatments are applied.

Answer 18

experimental units

Question 19

When the experimental units are human beings, they often are called (blank).

Answer 19

subjects

Question 20

4 basic principles for designing experiments

Answer 20

1. Comparison.
2. Random assignment
3. Control
4. Replication

Question 21

An observed effect so large that it would rarely occur by chance is called (blank).

Answer 21

statistically significant

Question 22

A statistically significant association in data from a well-designed experiment does imply
causation.

Answer 22

True

Question 23

In a (blank), the treatments are assigned to all the experimental
units completely by chance.

Answer 23

completely randomized design

Question 24

Some experiments may include a (blank) that receives an inactive treatment or an existing baseline treatment.

Answer 24

control group

Question 25

The response to a dummy treatment is called the (blank).

Answer 25

placebo effect

Question 26

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

Answer 26

double-blind experiment

Question 27

A (blank) is 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 27

block

Question 28

In a (blank), the random assignment of experimental units to treatments is carried out separately within each block.

Answer 28

randomized block design

Question 29

A (blank) is a randomized blocked experiment in which each block
consists of a matching pair of similar experimental units.

Answer 29

matched pairs design