statistics-and-probaility.pdf

Meaning of Statistics
STATISTICS AND PROBABILITY
Abdulrahamn M. Ismael
Senior High Department
Philippine Engineering and Agro-industrial Colllege, Inc.
Marawi City
ismael.am67@msumain.edu.ph
January 27, 2022
Abdulrahman M. Ismael STATISTICS

What is Statistics
A Statistics is a science which deals on the collection of data,
presentation of the collected data, and interpretation of the
results so as to yield meaningful information.

What is Statistics
Population
The totality of the observation of which a study is concerned
about is called the population of the study. Population can
refer to the subjects of the study or the observations themselves.

What is Statistics
Population
The totality of the observation of which a study is concerned
about is called the population of the study. Population can
refer to the subjects of the study or the observations themselves.
Example1
if a study is conducted to determine the PEACI student's
opinion on the possible tuition fee increase, and if there are
16,000 students, we say that we have a population with nite
size of 16,000.

Example2
If one is interested to nd out the choice among the senatorial
candidates in a coming election, the population of the study is
the set of registered voters in that coming election.

Example2
Take Note!
A study that takes data from the entire population is called a
census.

Example2
Take Note!
A study that takes data from the entire population is called a
census.
Sample
study only a part of the population which we call a sample.
Ideally, the sample must be taken in such a way that it
represents the population very well.

Importance of Statistics
Some uses of statistics that we will also encounter for in this
course and they are as follows:

helps in proper and ecient planning of a statistical inquiry
in any eld of study. Like aiding in the method of collecting
data, deciding on the sample size and the process of
selecting the sample. It will also help you in deciding the
appropriate data to be collected.

aids in presenting complex data in a suitable tabular and
graphical form for an easy and clear comprehension of the
data.

data.
provides us tools that can be used in understanding the
nature and pattern of variability of a phenomenon or a set
of observation.

data.
provides us tools that can be used in understanding the
nature and pattern of variability of a phenomenon or a set
of observation.
can help us make reliable inferences about the population
even when the data comes only from sample.

can help you understand and discover the relationships
between variables.

between variables.
helps you how to obtain reliable forecasts.

between variables.
it can aid in making decisions on how to improve processes.

between variables.
Variables and Types of Data
In order to gain information about seemingly haphazard events,
statisticians collect data for variables used to describe the
event.

between variables.
event.
A variable is a characteristic or attribute that changes or
varies over time and/or for dierent individuals or objects
under consideration.

between variables.
event.
A variable is a characteristic or attribute that changes or
varies over time and/or for dierent individuals or objects
under consideration.
An experimental unit is the individual or object on
which a variable is measured. A single measurement or
data value results when a variable is actually measured on
an experimental unit.

Data are the values (measurements or observations) that
the variables can assume. Variables whose values are
determined by chance are called random variables.

Data are the values (measurements or observations) that
the variables can assume. Variables whose values are
determined by chance are called random variables.
Example3
Sppose that an insurance company studies its records (called
data) about the number of automobiles involved in car accident.
On their records, they observed that on the average, 3 out of
every 100 automobiles were involved in an accident every year.
Although there is no way to predict the specic automobiles
that will be involved in an accident (a random occurrence), the
company can adjust its rates accordingly since the company
knows the general pattern over the long run. That is, on the
average, 3 percent of the insured automobiles will be involved in
an accident each year.

A collection of data values forms a data set. Each value in the
data set is called a data value or datum. Variables can be
classied into two categories: qualitative or quantitative
Qualitative variables are variables that measure the
quality or characteristic on each experimental unit. It
produce data that can be categorized according to
similarities or dierences in kind often called categorical
data. For example, gender, political aliation and religious
preference.

A collection of data values forms a data set. Each value in the
data set is called a data value or datum. Variables can be
classied into two categories: qualitative or quantitative
Qualitative variables are variables that measure the
quality or characteristic on each experimental unit. It
produce data that can be categorized according to
similarities or dierences in kind often called categorical
data. For example, gender, political aliation and religious
preference.
Quantitative variables are variables that measure the
numerical quantity or amount of each experimental unit. It
can be ordered or ranked. For example, heights, weights,
volume and body temperatures.

Quantitative variables are classied into two groups: discrete
and continuous.
1 Discrete variables
Discrete variable can assume only a nite or countable
number of values. This can be assigned values such as 0, 1,
2, 3, and are said to be countable.
Example4: Number of children in a family, number of
students in a classroom, number of calls received by a
switchboard operator each day for one month.

Quantitative variables are classied into two groups: discrete
and continuous.
1 Discrete variables
Discrete variable can assume only a nite or countable
number of values. This can be assigned values such as 0, 1,
2, 3, and are said to be countable.
Example4: Number of children in a family, number of
students in a classroom, number of calls received by a
switchboard operator each day for one month.
2 Continuous variables
Continuous variable can assume an innite number of
values between any two specic values. They are obtained
by measuring and often include fractions and decimals.
Example5:
(a) Temperature is a continuous variable since the variable
can assume all values between any two given temperatures.
(b) Heights might be rounded to the nearest inch, weights
to the nearest ounce, etc. Hence, a recorded height of 73
inches could mean any measure from 72.5 inches up but not

Data can be used in dierent ways. Depending on how they are
used, the body of knowledge on statistical methods is divided
into two main areas or branches, namely Descriptive
Statistics and Inferential Statistics.
Two Major Areas in Statistics

Data can be used in dierent ways. Depending on how they are
used, the body of knowledge on statistical methods is divided
into two main areas or branches, namely Descriptive
Statistics and Inferential Statistics.
Two Major Areas in Statistics
1 Descriptive Statistics. It comprises of those statistical
tools which deal on the presentation of the observed data
that can be done in various forms such as tables, graphs
and diagrams or describing the data through computation
of measures that summarize the characteristics of the set of
data.
Example6:
Consider the national census conducted by the philippine
Statistics Oce (PSO) every 10 years. Results of this
census give the average age, income, and other
characteristics of the Philippine population. The NSO also
presents the data in some meaningful form such as charts,
graphs, or tables.

Cont....

Cont....
1 Inferential Statistics. It consists of those statistical tools
concerned with generalizing results from random samples to
populations, performing estimations and hypothesis tests,
determining relationships among variables, and making
predictions.
Example7:
Suppose we want to know the percentage of illiterates in
our country. We take a random sample from the population
and nd the proportion of illiterates in the sample. With
the aid of other statistical measures and probability, we
make some inferences or general statements about the
population proportion of illiterates.

Assignment1: Due Feb. 01, 2022
In each statement that follows identify whether descriptive or
inferential statistics is used.

1 The average price of a unit of Camella homes sold in
Cagayan de Oro during the week of April 22 − 28, 2012 was
PhP 1, 051, 053.

PhP 1, 051, 053.
2 According to Provincial Statistics Oce, 85 percent of the
workers in their province get to work in public utility
vehicle.

PhP 1, 051, 053.
vehicle.
3 The National Eye Institute has halted a clinical trial on a
type of eye surgery, calling it ineective and possibly
harmful to a person's vision.

PhP 1, 051, 053.
vehicle.
4 Allergy therapy may make bees go away (Prevention,
April 1995).

PhP 1, 051, 053.
vehicle.
4 Allergy therapy may make bees go away (Prevention,
April 1995).
5 Drinking decaeinated coee can raise cholesterol levels by
7 percent.

Cont.....

Cont.....
1 It is predicted that the average number of automobiles each
household owns will increase next year.

Cont.....
2 The average number of students in a class in PEACI is 22.6.

Cont.....
3 Last year's total attendance of Azkal's football games was
50,000.

Cont.....
3 Last year's total attendance of Azkal's football games was
50,000.
4 According to the Court of Justice of the Philippines, 14
percent of trial-ready civil actions and equity cases during
1993 were decided in less than six months.

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