Biostatistics : Types of Variable

Types of
Variables
Duration: ≈ 60 Minutes
Dr Tarekk Alazabee
2012
Libyan National Center for Diseases Control

Main objectives
After completing this presentation, the
participants will able to:
- Define Statistics and Biostatistics.
- Define and identify the different types of data
and understand why we need to classifying
variables.

Agriculture
Economy
Industry
Dr Tarekk

In Public Health
- Some of the statistics most often
encountered are called means,
standard deviation, percentages,
and rates.
Dr Tarekk

◘ What is the data?
◘ What is statistics?
◘ What is biostatistics?
Dr Tarekk

What is the data?
 The data is the raw material of
statistics.
 The data could be numbers or
categories or both.

Statistics
Latin:
Status: “manner of standing” or “Position“.
‫نحن‬ ‫هل‬
‫ضائعون؟‬ ‫اآلن؟‬ ‫أقف‬ ‫أين‬
Dr Tarekk

Data Information
Statistics
Dr Tarekk

  
   
    Part of Data
Dr Tarekk

The purpose: To determine the nature
of the information
The field of study concerned with:
o The collection, organization, summarization,
and analysis of data. ( Descriptive Statistics).
o The Drawing of inferences about body of
data when only a part of the data is observed.
( Inferential Statistics ).
Definition
Dr Tarekk

What is Biostatistics?
Dr Tarekk

Biostatistics
 Is Statistics applied to
biological sciences and
medicine.
Dr Tarekk

 Routinely Kept Records.
 Surveys.
 Experiments.
 External Sources
Dr Tarekk

‫المتغيــرات‬ ‫أنـــواع‬
Dr Tarekk

 Variable:
Characteristic that can take on different
values for different persons, places or
things.
Exp: Age, Gender, Blood pressure
Statistical analysis need variability;
otherwise there is nothing to study
Definition

Variables
Qualitative V Quantitative V
Continuous V Discrete V
Types of Variables
Dr Tarekk

I. Quantitative Variable ( Numerical V)
- Measurements made on quantitative
variables convey information
regarding amount.
Quantitative Variable
- Discrete V
- Continues V

a) Discrete V (Countable):
Is characterized by gaps or interruptions
in the values that it can assume.
Exp: No of admissions.
No of decayed teeth per child.
I. Quantitative Variable
1 2 3 4
Dr Tarekk

b) Continuous V (Measurable):
can assume any value within
a specified relevant interval of
values.
Exp: Age. Blood Sugar. Height. Weight
Dr Tarekk

100 230
7 Years 25 Years
Dr Tarekk

II. Qualitative (Nominal) Variable:
- Some characteristics are not
capable of being measured in
the sense, and can be categorized
only.
Dr Tarekk

O
AB
B
A
Blood
Group


Gender
Male
Female
Qualitative (Nominal) Variable:
Dr Tarekk

Justification
Statistical
Tests
Data
Presenting
Data
Summarizing
Types of
the Variables
Scales of
Measurement
Dr Tarekk

Dr Tarekk
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Biostatistics : Types of Variable

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