DO NOW- DAY 2

Journal (write!)
In 1-2 sentences, what do you think
“correlation” means?

HOMEWORK REMINDERS
Due today: Descriptive research methods “exit ticket”
Due next class: Naturalistic Observation!
 Hopefully nothing else, but it depends on how much we get through today!!

AGENDA
1. Crash Course review
2. Correlational Research lesson

3. Past AP exam FRQ (together)
4. Analyzing correlations review
5. Exit ticket

CRASH COURSE REVIEW

CHAPTER 1 AGENDA
•

Day 1- Descriptive Research Methods

•

Day 2- Correlational Research

•

Day 3- Experimental Research

•

Day 4- Ethics/Statistics

•

Day 5- Chapter 1 Exam

OBJECTIVES
Differentiate types of research with regard to purpose, strengths, and weaknesses
Describe how research design drives the reasonable conclusions that can be drawn

CORRELATIONAL RESEARCH
Describing behavior is the first step toward predicting it.
When surveys and naturalistic observations reveal that one trait or behavior accompanies another, we say the two correlate.
Correlation reveals how closely the two things link together and how well it predicts the other.

TYPES OF CORRELATION
Positive- the presence of one thing predicts the presence of another
Negative- the presence of one thing predicts the absence of another

Zero- no correlation/relationship exists

Strong
Weak

CORRELATION
 Scatterplot
 a graphed cluster of dots, each of which represents the values of two variables
 the slope of the points suggests the direction of the relationship
 the amount of scatter suggests the strength of the correlation
 little scatter indicates high correlation
 also called a scattergram or scatter diagram

DRAW ‘DEM GRAPHS
Grades and time studying
Grades and skipping class

CORRELATION


Correlation Coefficient

Indicates direction of relationship
(positive or negative)
Correlation
coefficient

r = +.37

Indicates strength of relationship
(0.00 to 1.00)

CORRELATION
 Positive Correlation: score between
0 & +1. The two things either increase or decrease together
(direct relationship).
 Negative Correlation: scored with a negative (-) sign; means there is an inverse relationship. As one thing increases the other decreases.
 Correlation Coefficient – a statistical measure of the extent to which 2 factors vary together and thus how well either factor predicts the other
 + or – indicates the direction of the relationship  0.00 to 1.00 indicates the strength of the relationship
 r= +.68

Scatterplots, showing patterns of correlations

CORRELATION
Examples
 If your level of test anxiety goes down as your time spent studying for the exam goes up, would you say these events are positively or negatively correlated?
 True or False: If height and IQ were determined to be positively correlated, then tall people would have higher IQs.

CORRELATION
Height and Temperament of 20 Men
Height in
Subject Inches Temperament

1
2
3
4
5
6
7
8
9
10

80
63
61
79
74
69
62
75
77
60

75
66
60
90
60
42
42
60
81
39

Height in
Subject Inches Temperament

11
12
13
14
15
16
17
18
19
20

64
76
71
66
73
70
63
71
68
70

48
69
72
57
63
75
30
57
84
39

CORRELATION
95
Temperament 90 scores 85
80
75
70
65
60
55
50
45
40
35
30
25
55

60

65
70
Height in inches

75

Scatterplot of Height and Temperament

80

85

CORRELATION
Illusory Correlation: statistics can help us see what the naked eye sometimes misses. Correlations not only make visible relationships that we might