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