Coefficient Correlation

1. PRESENTATION ON
COEFFICIENT CORRELATION
BY
IRSHAD NAREJO
STATISTICSS FOR EDUCATION

2. DEFINITION
Correlation refers to a technique used to
measure the relationship between two or
more variables.
A correlation coefficient is a statistical
measure of the degree to which changes to
the value of one variable predict change to
the value of another.
A correlation can only indicate the presence
or absence of a relationship, not the nature
of the relationship. Correlation is not
causation.

3. CORRELATION COEFFICIENT FORMULA:
OVERVIEW.
Correlation coefficient formulas are used to
find how strong a relationship is between
data. The formulas return a value between
-1 and 1, where:
1 indicates a strong positive relationship.
-1 indicates a strong negative
relationship.
A result of zero indicates no relationship
at all.

5. POSITIVE CORRELATION
 Association between variables such that high scores
on one variable tend to have high scores on the other
variable
 A direct relation between the variables

6. NEGATIVE CORRELATION
Association between variables such that high scores on
one variable tend to have low scores on the other
variable.
An inverse relation between the variables

7. CORRELATION COEFFICIENT FORMULA
One of the most commonly used
formulas in statistic is
Pearson’s correlation coefficient formula.

8. SPSS VS HAND CALCULATION
X Y XY X2 Y2
0 8 0 0 64
2 10 20 4 100
3 4 12 9 16
6 6 36 36 36
9 1 9 81 1
10 3 30 100 9
30 32 107 230 226
N ∑XY - ∑X ∑Y
r =
[ N ∑X2 – (∑X)2] [N ∑Y2 – (∑Y)2]
(6 X 107) – 30 (32)
[6 (230) – 302] [6 (226) – 322 ]
r = -.797 (note cross
products term in the
numerator is negative)
and R-square = .635

9. SPSS VS HAND CALCULATION
Correlations
1 -.797*
.029
6 6
-.797* 1
.029
6 6
Pearson Correlation
Sig. (1-tailed)
N
Pearson Correlation
Sig. (1-tailed)
N
Shyness
Speeches
Shyness Speeches
Correlation is significant at the 0.05 level (1-tailed).*.

10. *Thank you*