Chapter 5: Variables in Research

Question 1

How are variables related to theoretical concepts? Provide an example.

Question 2

Distinguish between independent variables and dependent variables. Give examples.

Answer 2

dependent variables are meant to alter when the independent variable is altered

Question 3

Why is it not accurate to say that the independent variable is the cause and the dependent variable is the effect? Provide an example.

Answer 3

Because you do not always know which is the cause and which one is the effect, it is more accurate to discuss their (relevance??)

Violent video games

Question 4

What are the levels of an independent variable?

Answer 4

A level is a different value of an independent variable such as placebo or non-placebo

Question 5

What are the considerations when choosing the levels of an independent variable?

Question 6

Distinguish between quantitive and categorical variables. Give examples.

Answer 6

quantitive-altered by amount
categorical-altered by kind or type

Giving different amounts of water to a plant is quantitive, choosing which fertalizer to give to the plant is categorical

Question 7

What is the difference between continuous and discreet variables?

Answer 7

discreet variables cannot have intermediate measurements like a person cannot commit 1.3 crimes. A continuous variable can have intermediate measurements such as someone lifting 101.675 pounds.

Question 8

Define: measurement

Answer 8

the process of assigning numbers to events or objects according to rules

Question 9

List the four types of measurement scales.
Describe the four types of measurement scales. What are their properties? Give examples.

Answer 9

Nominal Scale
Ordinal Scale

Question 10

What is a nominal scale? Provide an example.

Answer 10

a measure that simply divides objects or events into categories according to their similarities or differences (p125)

The nominal scale gives information only about whether two events are the same or different. (127)

Question 11

What is an ordinal scale? Provide an example.

Answer 11

a measure that both assigns objects or events a name and arranges them in order of their magnitude (p125)

The ordinal scale does that too, but also gives us a ranking on some variable.

Question 12

What is an interval scale? Provide an example.

Answer 12

a measure in which the differences between numbers are meaningful; includes both nominal and ordinal information

The interval scale conveys nominal and ordinal information, and also allows us to make quantitative statements about the magnitude of the differences between events.

Question 13

Why does Nico’s mother know more about his liking for vegetables than Jessica’s mother does about Jessica’s vegetable preferences. (126) [Difference between ordinal and interval scale]

Answer 13

Nico’s scale was more specific. Jessica rated her least to most favorite simply by rank while Nico rated his through a numerical value that illustrates the interval gap between favoirites
ex 5,4,3,2,1-Jessica
ex 5, 3.3, 2.4, 1.6-Nico

Question 14

What is a ratio scale. Provide an example of a meaningful and meaningless zero.

Answer 14

a measure having a meaningful zero point as well as all of the nominal, ordinal, and interval properties

A meaningless zero is like rate your preference fomr 0-10 where it just adds to your bottom end of the same measurment. If 0 meant neutral or nothing it has a meaning as a separate measurment

The ratio scale contains all the information of the other three scales, as well as conveying information about ratios of magnitudes.

Question 15

Is a person with an IQ of 120 “twice” as smart as someone with an IQ of 60? Why or why not?

Question 16

Provide an alternate example from the textbook that explains the difference between reliability and validity. Give an example that is valid but nor reliable and the reverse.

Question 17

Define reliability of a test measure. What are the types of reliability of measures? Give an example of each.

Answer 17

Test-retest reliability and internal consistency reliability

1-take the same test and get the same results
2-split the test questions in half and see if the person scores evenly on both tests (ie see if they are measuring the same thing)

Question 18

List each type of validity in relation to tests and measurement and provide an example of each

Answer 18

(1) construct validity,
(2) face validity,
(3) content validity
(4) criterion validity

Question 19

Define construct validity

Answer 19

a test that the mea- surements actually mea- sure the constructs they are designed to measure, but no others (131)

*it can readily make predictions about what it tests!

Question 20

Define face validity

Answer 20

idea that a test should appear superficially to test what it is supposed to test (131)

ie can the layman see the validity

Question 21

Define content validity

Answer 21

idea that a test should sample the range of behavior represented by the theoretical concept being tested (132)

ie it measures all that is chiefly relevant and not just one aspect of a thing (intelligence tests)

Question 22

Define criterion validity

Answer 22

idea that a test should correlate with other measures of the same theoretical construct (132)

ie an intelligence test will measure things people and research commonly agree requires intelligence

Question 23

Using a bathroom scale as an example, explain how a measurement can be both reliable and invalid.

Question 24

Distinguish between real and apparent limits. Why are they relevant to independent variables?

Answer 24

Real limits are the rounded number to the next interval. A person may be 5’87645 tall but we would say 5’8 whereas the apparent limit is the specific number

Question 25

Define variable of interest

Answer 25

a variable of interest is when it is unclear which variable is the cause and which is the effect

Question 26

Define subject variable

Answer 26

variables that the researcher does not manipulate. Examples could include status of wealth of the subject or IQ

Question 27

Define confounded variable

Answer 27

A confounded variable is one that varies with the independent variable (122)
In other words, you cannot tell what is actually impacting the dependent variable.

Question 28

Define error variance

Answer 28

variability in the depen- dent variable that is not associated with the inde- pendent variable

Question 29

What is the difference between concurrent and predicted validity?

Answer 29

Concurrent-measures what is
predicted-measures what will be

Question 30

Define random error

Answer 30

This variability could be called random error (or error variance) because it is not associated with any known independent variable. (132)

ie slight unpredictable errors in the measuring tool

Question 31

Define systematic or constant error. When is it less of a problem and when is it more? Provide examples of each.

Answer 31

-measurement error that is associated with consistent bias

-It is less problematic if the error impacts the variables consistently and evenly

-It is more problematic when it confounds the independent variable