Invitation to Psychology

Chapter 1 What Is Psychology? 23

correlation is a numerical measure of the strength

of the relationship between two things. The things

may be events, scores, or anything else that can

be recorded and tallied. In psychological studies,

such things are called variables because they can

vary in quantifiable ways. Height, weight, age,

income, IQ scores, number of items recalled on

a memory test, number of smiles in a given time

period—anything that can be measured, rated, or

scored can serve as a variable.

A positive correlation means that high values

of one variable are associated with high values of

the other, and that low values of one variable are

associated with low values of the other:

Experimental Variables

of behavior or experience

that can be measured or

described by a numeric

scale.

positive correlation

An association between

increases in one variable

and increases in another,

or between decreases in

one and decreases in the

other.

Recite & Review

Recite: Say aloud to yourself or a study partner everything you can recall about representative

samples, descriptive methods, case studies, observational studies, psychological testing, and sur-

veys. See if you remember each method’s strengths and weaknesses.

Review: Next, go back and reread this section.

Now take this Quick Quiz:

A. Which descriptive method would be most appropriate for studying each of the following

topics? (They have all been investigated by psychologists.)

1. Ways in which the games of boys differ from those of girls


2. Changes in attitudes toward nuclear disarmament after a TV
   movie about nuclear holocaust


3. The math skills of children in the United States versus Japan


4. Physiological changes that occur when people watch violent
   movies


5. The development of a male infant who was reared as a female
   after his penis was^ accidentally burned off during a routine
   surgery

Study and Review at mypsychlab

validityB. a5. c4. e3. d2. b1. A.

a. case study

b. naturalistic

observation

c. laboratory

observation

d. survey

e. test

B. Professor Flummox gives her new test of aptitude for studying psychology to her psychology

students at the start of the year. At the end of the year, she finds that those who did well on

the test averaged only a C in the course. The test lacks __________.

Answers:

You are about to learn...

• what it means to say that two things, such
as grades and TV watching, are “negatively”
correlated.

• whether a positive correlation between TV
watching and hyperactivity means that too
much TV makes kids hyperactive.

Correlational Studies:

looking for relationships

In descriptive research, psychologists often want
to know whether two phenomena are related
and, if so, how strongly. Are students’ grade-point
averages related to the number of hours they
spend watching TV shows, playing video games,
or texting? To find out, a psychologist would do a
correlational study.

Measuring Correlations

LO 1.13, LO 1.14

The word correlation is often used as a syn-
onym for “relationship.” Technically, however, a

correlational study A

descriptive study that

looks for a consistent

relationship between two

phenomena.

correlation A measure

of how strongly two vari-

ables are related to each

other.

Variable X Variable Y

Positive Correlation:

The higher X is,

the higher Y is.

Height and weight are positively correlated;

so are IQ scores and school grades. Rarely is a