These slides describe detail topic correlation.

1. Program: Pharm-D 4th
Semester: II (2019-20)
Course: Bio-Statistics
Course code: PHAR-03428
Class Teacher: DR. LIAQUAT AHMAD
email: liaquatahmad@uvas.edu.pk
Lecture # 28-30

2. Linear Correlation Coefficient

5. Types of Correlation

7. Positive Correlation

9. Negative Correlation

10. No Correlation

13. Systolic and diastolic Blood Pressure Values for a sample of
48 Elderly Men

14. Scatter Diagram

16. Formulas of r

21. Calculate Correlation coefficient between height and dead space
of 10 children
Height (cm) Dead Space (ml)
110 44
116 31
124 43
129 45
131 56
138 79
142 57
150 56
153 58
155 92

25. Properties of Correlation Coefficient
• The coefficient of correlation always lies between –1 and 1,
including both the limiting values i.e.
That is, -1 ≤ r ≤ 1
• If the linear correlation coefficient takes values closer to −1,
the correlation is strong and negative, and will become
stronger the closer it approaches −1.
• If the linear correlation coefficient takes values close to 1, the
correlation is strong and positive, and thus will become
stronger the closer it approaches to 1.

26. • The Coefficient of Correlation is a unit-free
measure.
• he coefficient of correlation remains invariant
under a change of origin and/or scale of the
variables under consideration depending on the
sign of scale factors.
• In a linear regression, r is the geometric mean
of two regression coefficients.

27. Weights and Heights Data

28. Calculate r.

30. Important Formulas