Transcript Correlation - mrswhitworths

Scientific Method
Create testable
operational
definitions
Be curious.
Question your
world.
Collect data using
DESCRIPTIVE
Research
Conduct more
research
Naturalistic
Observation
Survey
Case
Study
Form a
Hypothesis
Relationship?
CORRELATION
Causation?
EXPERIMENT
Doesn’t support
the hypothesis
Continue to
retest
Use this to
predict and
explain the world
Supports the
hypothesis
Create a Theory
Essential Questions
• EQ 1-3: How do psychologists use the
scientific method to study behavior and
mental processes?
• EQ 1-4: What are the strengths and
weaknesses of the different research
methods?
• EQ 1-5: How do psychologists draw
appropriate conclusions about behavior
from research?
Scientific Method
Create testable
operational
definitions
Be curious.
Question your
world.
Collect data using
DESCRIPTIVE
Research
Conduct more
research
Naturalistic
Observation
Survey
Case
Study
Form a
Hypothesis
Relationship?
CORRELATION
Causation?
EXPERIMENT
Doesn’t support
the hypothesis
Continue to
retest
Use this to
predict and
explain the world
Supports the
hypothesis
Create a Theory
Be curious!
1. Does involvement in HS athletics improve academic
performance?
2. Does excessive texting impede face-to-face relationships?
3. Does personality influence musical preferences?
4. Do ads portraying unrealistic body types reduce the selfimage of the viewer?
5. Does student consumption of caffeine in the morning
improve first period grades?
6. Does gamification of the classroom improve increase
student engagement?
Be curious!
7. Does a community service requirement positively or
negatively impact student opinions of community service?
8. Does HR increase communication in a large suburban HS?
9. Do teacher websites improve student performance in class?
10. Does focus on minor rules (flip-flops and hats) reduce
student adherence to major rules (insubordination or class
cutting)?
Hypothesis
Hypothesis is a testable prediction that
lets us accept, reject or revise a theory.
If families do not stress gender
differences then there will be fewer sex
differences in siblings.
Theory
Theory is an EXPLANATION that
integrates principles, organizes and
PREDICTS behaviors or events.
Families influence the gendering of their
children.
Astrology
•
•
•
•
•
•
•
•
•
•
•
•
Aries (March 21–April 19)
Taurus (April 20–May 20)
Gemini (May 21–June 21)
Cancer (June 22–July 22)
Leo (July 23–August 22)
Virgo (August 23–September 22)
Libra (September 23–October 22)
Scorpio (October 23–November 21)
Sagittarius (November 22–December 21)
Capricorn (December 22–January 19)
Aquarius (January 20 –February 18)
Pisces (February 19–March 20)
Answers
•
•
•
•
•
•
•
•
•
•
•
•
E Aries (March 21–April 19)
B Taurus (April 20–May 20)
C Gemini (May 21–June 21)
A Cancer (June 22–July 22)
F Leo (July 23–August 22)
D Virgo (August 23–September 22)
K Libra (September 23–October 22)
H Scorpio (October 23–November 21)
I Sagittarius (November 22–December 21)
L Capricorn (December 22–January 19)
J Aquarius (January 20 –February 18)
G Pisces (February 19–March 20)
Research Methods in Psychology
• Correlational Research
– Research technique based on the naturally
occurring relationship between two or more
variables
– Used to make PREDICTIONS, such as the
relation between SAT scores and success at
college
– Cannot be used to determine cause and effect
Scatterplots
Perfect positive
correlation (+1.00)
Scatterplot is a graph that comprises of points
generated by values of two variables.
The slope of points depicts the direction,
The amount of scatter shows the strength of
relationship.
Scatterplots
Perfect negative
correlation (-1.00)
No relationship (0.00)
Scatterplot on the left shows a relation between the
variables, and the one on the right shows no relationship
between the two variables.
Correlation
When one trait or behavior accompanies
another, we say the two correlate.
Indicates strength
of relationship
(0.00 to 1.00)
Correlation
coefficient
Correlation Coefficient is a
statistical measure of relationship
between two variables.
r = + 0.37
Indicates direction
of relationship
(positive or negative)
Operational Definition
• An exact description of how to derive a
value for a characteristic you are
measuring. It includes a precise
definition of the characteristic and how,
specifically, data collectors are to
measure the characteristic.
• What you are studying determines the
type of data you get.
Study of
Low Self Esteem and Depression
• You do the research because you assume
the two are related
• Compare two variables
– Variable 1 = Score on a self-esteem test
– Variable 2 = Length of a bought of depression
in months
–Score on a self-esteem test
–Length of a bought of depression in
months
Correlation and Causation
or
Correlation is not Causation:
It only predicts!!!!
•
Children with big feet reason better than
children with small feet.
–
•
(Children who are older have bigger feet than
younger children; thus they can reason better)
Study done in Korea: The most predictive factor
in the use of birth control use was the number of
appliances in the home.
–
(Those who have electrical appliances probably have
higher socioeconomic level, and thus are probably
better educated.)
Correlation is not Causation:
It only predicts!!!!
•
People who often ate Frosted Flakes as children
had half the cancer rate of those who never ate
the cereal. Conversely, those who often ate
oatmeal as children were four times more likely
to develop cancer than those who did not.
–
Cancer tends to be a disease of later life. Those who
ate Frosted Flakes are younger. In fact, the cereal was
not around until the 1950s (when older respondents
were children, and so they are much more likely to
have eaten oatmeal.)
In a Gallup poll, surveyors asked, “Do you
believe correlation implies causation?’”
• 64% of American’s answered “Yes” .
• 38% replied “No”.
• The other 8% were undecided.
The Simpsons
(Season 7, "Much Apu About Nothing")
Homer:
Not a bear in sight. The
"Bear Patrol" is working like a charm!
Lisa: That's specious reasoning, Dad.
Homer:
[uncomprehendingly]
Thanks, honey.
Lisa: By your logic, I could claim that
this rock keeps tigers away.
Homer:
Hmm. How does it work?
Lisa: It doesn't work; it's just a
stupid rock!
Homer:
Uh-huh.
Lisa: But I don't see any tigers
around, do you?
Homer:
(pause) Lisa, I want to
buy your rock.
Consider the following research undertaken by
the University of Texas Health Science Center at
San Antonio appearing to show a link between
consumption of diet soda and weight gain.
The study of more than 600 normal-weight people
found, eight years later, that they were 65
percent more likely to be overweight if they
drank one diet soda a day than if they drank
none. And if they drank two or more diet sodas
a day, they were even more likely to become
overweight or obese.
Third or Missing
Variable Problem
A relationship other than causal
might exist between the two
variables. It's possible that
there is some other variable or
factor that is causing the
outcome.
• Ice cream sales and the number of
shark attacks on swimmers are
correlated.
• Skirt lengths and stock prices are highly
correlated (as stock prices go up, skirt
lengths get shorter).
• The number of cavities in elementary
school children and vocabulary size are
strongly correlated.
There are two relationships which
can be mistaken for causation:
1. Common response
2. Confounding
1.
Common Response:
Both X and Y respond to changes in
some unobserved variable, Z. All
three of our previous examples are
examples of common response.
There are two relationships which
can be mistaken for causation:
1. Common response
2. Confounding
1.
Common Response:
Both X and Y respond to changes in
some unobserved variable, Z. All
three of our previous examples are
examples of common response.
Illusory Correlations
• Redelmeier and Tversky (1996) assessed 18
arthritis patients over 15 months, while also taking
comprehensive meteorological data. Virtually all
of the patients were certain that their condition
was correlated with the weather.
• In fact the actual correlation was close to zero.
• Usually when the data in question stands out
Essential Questions
• EQ 1-3: How do psychologists use the
scientific method to study behavior and
mental processes?
• EQ 1-4: What are the strengths and
weaknesses of the different research
methods?
• EQ 1-5: How do psychologists draw
appropriate conclusions about behavior
from research?