7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 1/6

 

1 | P a g e  

Introduction lecture of biostatics

 At first the Dr talked about the exams: 

Now let us start with biostatistics definition, its composed of two word :

BIO: anything alive.

Statistics: calculation or deal with data.

So, biostatistics: the wild range biological application of statistics, on other 

words it’s the science which deal with the development and application of 

data collection (collect, summarize and analyze data ) data that subject to

random variation .

 WHY WE USE STATISTICS? 

Statistics is useful, every one of us use statistics so we should keep it in

mind and use it because it’s very useful in our life, its depend on the person

who use the statistics and the person who lessen to the presentation.

EX: if we have a class with 2 students , one of them after the exam said “I’m the 2nd one in the class “ But the other student said “ he is the last one

in his class “ we have 2 word ( 2 presentation ) and the same meaning .the

interpretation that if somebody don’t know the total number of student then

he said “ the second one is excellent “ also, he will said “ the last one in the

class is bad “ ,,,, So, we have a serious problem .

 NOTE:

*** every one use statistics.

*** statistics gives the right answer ( 95%) of the time .

WHY WE SAID (95%)?? 

because it interpret in areaway, for example: someone wanted to study the

relation between the color of the cars and the accidents so, he asked the

1st exam will be on 11/3/2013

2nd exam will be on 15/4/2013

That mean you need to make a decision by analyzing collecting data

7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 2/6

 

2 | P a g e  

police to record the color of the car which make an accident , at the end of 

his study he found that most of the car has red color So, he conclude that :

To reduce car accident the government should prevent selling red car ( I

think he is a stupid man :p) , this is wrong , no relation between the color and the

rate of accident .But if he said the young driver make more accident, he will almost right  

so it’s the age of the driver which is decide the range of accidents , not the

color of the car.

 WHY STATISTICS? EXAMPLES: 

* Which drugs should be allowed on the market?

* What public health programs should be pursued?

* Are cell phones a good idea for drivers?

* Is it a good idea for post-menopausal women to take estrogen?

 WHAT IS THE RULE OF STATISTICS IN OUR STUDIES?

To guide the design of an experiment, so we need data to answer the

question and we get data by using random variation. To collect data we

need a sample ( apart of population ) , you should know that we have

different types of sample and different types of sampling techniques.

Nowadays you are very lucky because computers doing all statistical

analysis, especially if you are familiar of excel, But even when you use

excel you should tell the program what you want (the calculation you want

the computer doing to you) because you determined the type of study.

In Jordan University in Amman we have a department which collect data about Jordanian, and

present the result to the decision makers.

EX: most of people in favor of raising the price of benzene  

REMEMBER:

statistics is the science and art of collecting, summarizing, and analyzing data that are subject

to random variation. It’s the application of statics on biological problem. 

7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 3/6

 

3 | P a g e  

 VARIABLES:

Its characteristics that takes different values in different persons, places,

or things.(quantities that varies).

EX:  blood pressure, heart rate, height of adult males, weight of new borne

babies, ages of patients, grade, and gender.

DATA:It’s the number that results from measurement or counting. 

 SOYRCES OF DATA:

1) RECORDS : (hospital medical records, the number of mortality infants).It’s agood sources of data. But remember not everything in the record is

correct. Because some record is done for special cases. EX: not everything

we hear or see on the newspaper or T.V is true.so; we should care in our 

interpretation of the data which presented to us.

2) SURVEYS : we use it when we can’t find the data in the records (the blood

groups of students in science hall2).

3) EXPERIMENTS : (best strategy for patient compliance EX: the effect of different

drug on body weight)

****in the record and experiment the data is present to you but it isn’t present in 

the survey so, you should study a special sample to get the data.

Like body weight and height, you need to measure

something. It can be 230.67 or 342 or 76.5 Kg … 

we can get digits. (CONTINOUS NUMBER).

Like the total number of students, it can be

201 students but it impossible to be 253.5.

we can’t get digits (DISCRET NUMBER).

7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 4/6

 

4 | P a g e  

 MOST DATA FALL INTO TWO CLASSES:

***Continuous data :  are used to report a measurement of the individual

that can take on any value within an acceptable range. EX: age, BP, and

change of weight over 6 month.

***Categorical data: are used to report a characteristic of the individual

that has a finite, usually smaller number of possibilities. EX: gender (male

or female), vital status (alive or dead), ever smoked (yes or no), blood

groups (A, B, AB and O).

 NOTE:

*** All biostatistics begins with description. Before you do anything else,

you look at the data and summarize the data. Summarize in simple, useful

and understandable way.

EX: you want talk about blood groups of the students in science hall2; you

summarize the information like that:

The total number of the students is 335 students. We have 130 of them

with group (A), 55 of them with (B) group, 80 of them with (O) group, and70 of them with (AB) group.

*** Statistics is just numerical summary of the data.

*** Descriptive statistics should be clear and easily interpreted. They should

not mislead you about the data they are summarizing.

COMMON TERMES USED IN STATISTICS:

* Population

* Sample* Variables

* Measurement

* Statistical inference

* Simple random sample

7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 5/6

 

5 | P a g e  

POPULATION:Population is the largest collection of entities for which we have an interest

at a particular time. (These entities have the same characteristics).

EX:  people, chair, classes, trees, any collection… It isn’t only referring to

the people. Also, it may be refer to special type of people like a population

of dental students, population of a police.

WE HAVE TWO TYPE OF POPULATION:

1) Finite population : values consist from fixed number.

2) Infinite population : values consist of endless succession of values.

 SAMPLE: It’s difficult to study the population one by one so we take a sample of 

them, then we study the sample, and we pass the conclusion from the

sample to the population.to pass the judgment from the sample to the

population the data should be represent the population.

Representative sample : the sample collected from the population where

every person or items of the population has the same chance of being

selected in the sample (random variation).SAMPLE : It’s a part of population. 

 VARIABLES: Something that we want to study, EX: weight, height, BP, blood groups,

grades, number of dental students, and the number of patient visiting your 

clinic.

**** FOR EACH ONE SAMPLE WE HAVE MANY VARIABLES.

REMEMPER: variables can be continuous related to the

measurement, and discrete related to counting  

7/29/2019 Scr.1 - Introduction Lecture of Biostatics

http://slidepdf.com/reader/full/scr1-introduction-lecture-of-biostatics 6/6

 

6 | P a g e  

 MEASUREMENT:The assignment of numbers to object or events according to a set of rules.

EX: weight, height … 

 STATICAL INFERENCE:Making the decision or taking interpretation (reach to the conclusion) we

use a basis of information contained in a sample that has been drawn from

that population.

EX: from previous classes we found that the average of dental students in

biostatistics is 78% so, we assume that dental students are very good

students, (in this example we make inference from base data).

DONE BY: HEBAH RAMADNEH  

...

.....

.... ......