MEDICAL STATISTICS

1. Understanding
Medical Statistics
and
ALI AHMED MAHAREAK
Assistant Lecturer Of Anesthesiology And
Intensive Care , Al-Azhar University

2. ‫على‬ ‫القدرة‬‫هو‬ ‫النجاح‬
،‫آخر‬‫إلى‬‫فشل‬ ‫من‬ ‫الخروج‬
‫الحماس‬‫فقد‬ ‫دون‬

3. Types of data
Categorical (qualitative) data
 Nominal Data that have no numerically
significant order, such as blood groups.
 Ordinal Data that have an implicit order of
magnitude, such as scores.
Numerical (quantitative) data

4. Types of Statistics
Descriptive Statistics ‫الوصفي‬ ‫االحصاء‬
Inferential Statistics ‫االستداللي‬ ‫االحصاء‬‫التحليلي‬
Parametric
Non-Parametric Tests

5. Descriptive Statistics
PERCENTAGES: An understanding of
percentages is the first and most important
concept to understand in statistics
MEAN : Otherwise known as average
It is used when the spread of the data normally
distributed
The mean is the sum of all the values, divided by
the number of values.
MEDIAN : Sometimes known as the mid-point
It is used to represent the average when the data
are not symmetrical, for instance the “skewed”
Distribution

6. MODE: It is used when we need a label for
the most frequently occurring event (ages of
patients with asthma in a practice)
STANDARD DEVIATION: SD indicates
how much a set of values is spread around the
average
 A range of one SD above and below the
mean (abbreviated to ± 1 SD) includes 68.2%
of the values.
 ±2 SD includes 95.4% of the data.
 ±3 SD includes 99.7%.

7. ‫بالثمار‬ ‫أعمالك‬‫على‬ ‫تحكم‬ ‫ال‬
‫بالبذور‬ ‫ولكن‬ ،‫جنيتها‬‫التي‬
‫زرعتها‬ ‫التي‬

8. P -VALUES
 The P (probability) value gives the
probability of any observed difference
having happened by chance.
P = 0.5 means that the probability of the
difference having happened by chance is 0.5 in
1, or 50:50.
P = 0.05 means that the probability of the
difference having happened by chance is 0.05
in 1, i.e. 1 in 20.

9. Choosing Inferential Statistics
deciding which inferential
statistics to use:
 Please consider how many variables are
being examined.
 If possible, the independent and dependent
variable(s).
 Consider the type of variables (categorical
vs quantitative/numerical).

10. Goal
Numerical
Measurement
Ordinal Data,
Rank, Score,
Nominal
Compare two paired
groups
Paired t test Wilcoxon test McNemar’s test
Compare two unpaired
groups
Unpaired t test
Mann-Whitney
test
Fisher’s test (Chisquare for
large sample)
Compare three or
more groups
One-way
ANOVA
Kruskal-Wallis
test
Chi-square test
Important Statistical tests

11. SPSS program

13. VARIABLE VIEW and Data Entry

14. DEFINE VARIABLES

17. Descriptive Statistics for nominal and ordinal data

18. Descriptive Statistics for Numerical data

20. Independent-Samples T-Test

21. Independent-Samples T-Test

22. Paired-Samples T-Test

23. Paired-Samples T-Test

24. One-Way-ANOVA

25. One-Way-ANOVA

26. One-Way-ANOVA

27. Chi-square test

28. Chi-square test

29. Mann - Whitney U test

30. Mann - Whitney U test