Basic Statistics

Statistics is a group of methods that are used to
collect, organize, present, analyze, and interpret
data to make decisions.

Collection refers to the gathering of information or
data.

Organization or presentation involves summarizing
data or information in textual, graphical, or tabular
forms.

Analysis involves describing the data by using
statistical methods and procedures.

Interpretation refers to the process of making
conclusions based on the analyzed data.

Descriptive Statistics

Inferential Statistics

 Descriptive Statistics
- is a statistical procedure concerned with
describing the characteristics and properties of a
group of persons, places, or things.
- Involves gathering, organizing, presenting, and
describing data.

For example, we may describe a collection of
persons by stating how many are poor and how
many are rich, how many are literate and how
many are illiterate, how many fall into various
categories of age, height, civil status, IQ, and
many more.

1. How many students are interested to take
Statistics online?
2. What are the highest and lowest scores
obtained by STENEX applicants this year?
3. What are the characteristics of the most
likable teacher according to students?
4. What proportion of SRSTHS students likes
Mathematics?

 Inferential Statistics
 is a statistical procedure that is used to draw
inferences or information about the properties or
characteristics by a large group of people, places, or
things on the basis of the information obtained from a
small portion of a large group.
 also called inductive reasoning or inductive
statistics.

 Example:
 Suppose we want to know the most favorite brand of
toothpaste of a certain barangay and we do not have
enough time and money to interview all the residents
of that barangay, we may just ask selected residents.
With the data obtained from the interviews, we shall
draw or make conclusion as to the barangay’s favorite
brand of toothpaste.

1. Is there a significant difference in the
academic performance of male and female
sophomore students in Statistics?
2. Is there a significant difference between
the proportions of students who prefer
Coke than Pepsi?
3. Is there a significant relationship between
amount of time studied and grades
received?
4. Is there a significant difference between
the Biology scores of 30 students before
and after taking Memory Plus for 15 days?

Descriptive Inferential
Sampling Distribution
Definition of Terms

Sampling Techniques Hypothesis Testing

• Z – test
Presentation of data • T – test
• F – test
• Test on Proportion
Summation • Chi-square test

Calculator Exercises
Correlation and Regression

Summary Measures of
Data

Normal Distribution

Tell whether the following situations will make use
of descriptive statistics or inferential statistics.
1. A teacher computes the average grade of her
students and then determines the top ten
students.
2. A manager or a business firm predicts future
sales of the company based on the present
sales.
3. A psychologist investigates if there is a
significant relationship between mental age
and chronological age.
4. A researcher studies the effectiveness of a new
fertilizer to increasing food production.
5. A janitor counts the number of various
furniture inside the school.

6. A sports journalist determines the most
popular basketball player for this year.
7. A school administrator forecast future
expansion of a school.
8. A market vendor investigates the most
popular brand of vinegar.
9. An engineer calculates the average height
of the buildings along Taft Avenue.
10. A dermatologist tests the relative
effectiveness of a new brand of medicine in
curing pimples and other skin diseases.

In this survey conducted by Pulse Asia:
1. Who were surveyed by Pulse Asia?
2. Is there anyone among you who
was a respondent in this research?
3. Why do you think Pulse Asia was
able to conclude the 69% favor RH
bill?

A population consists of all elements –
individuals, items, or objects – whose
characteristics are being studied. The
population being studied is called the target
population.
 A portion of the population selected for

study is referred to as a sample.

 Population – total number of SRSTHS students
during SY 2010-2011: 877 students
 Sample – Second year students of SRSTHS
during SY 2010-2011: 228 students
 Give your own examples!

 Elements or Members of a sample or population is a
specific subject or object(for example, a person, firm,
item, state or country)
Example: YOU as a member of the SRSTHS
population.
 Variable is a characteristic or property of a population
or sample which makes the members different from
each other.
Example: in II-Pasteur, gender is a variable
 Constant is a property or characteristic of a
population or sample, which makes the members of
the group similar to each other.
Example: if a class is composed of all boys, gender
is constant.
 Data (singular form is datum)are numbers or
measurements that are collected as a result from
observation, interview, questionnaire,
experimentation, test and so forth.

 Parameter is any numerical or nominal
characteristic of a population. It is a value or
measurement obtained from a population. It is
usually referred to as the true or actual value.
Example: The researcher uses the whole
population of SRSTHS to get the average
allowance of SRSTHS students.
 Statistic is an estimate of a parameter. It is any
value or measurement obtained from a sample.
Example: The researcher uses the sample
(n=200) to get the average allowance of SRSTHS
students.

 Qualitative data are data which can assume
values that manifest the concept of
attributes. These are sometimes called
categorical data.
Example: gender, nationality
 Quantitative data are data which are
numerical in nature. These are data
obtained from counting or measuring.
Example: Height, test scores

 Discrete Variables
 Continuous Variables
 Dependent Variables
 Independent Variables

 Discrete Variables – is one that can assume a
finite number of values. In other words, it
can assume specific values only. The values
of a discrete variable are obtained through
the process of counting.
Example: the number of chairs in a room
 Continuous Variables – A variable that can
assume any numerical value over a certain
interval or interval. The values of a
continuous variable are obtained through
measuring.
Example: The height of Kuya Ronil.

 Dependent Variable is a variable which is
affected or influenced by another variable.
 Independent Variable is one which affects or
influences the dependent variable.
Example:
In a research problem entitled,
“The Effect of Technology-based Instruction
on the Students’ Mathematics Achievement”.
The independent variable here is the
technology-based instruction, while the
dependent variable is the academic
achievement of students.

A. Classify the following as quantitative or
qualitative data
1. Color of the eye
2. Number of typewriters in a room
3. Civil status
4. Address
5. Telephone numbers
6. Age of teachers
7. Rank of students
8. Speed of a car
9. Birth rates
10. Score in mathematics examination

B. Identify each of the following as continuous or
discrete.
1. Weight of a body
2. Length of a rod
3. Number of chairs in the room
4. Dimensions of a table
5. Number of possible outcomes in throwing a die
6. Number of hairs on your head
7. Amount of sales in a business firm
8. All rational numbers
9. Speed of light
10. Area of a land
11. Lifetime of television tubes and batteries
12. Life span of a person
13. Number of passengers in a plane.

A. Google search or cut out newspaper clippings on a
research article on any topic. It should contain the results
of any survey conducted locally(preferred) or abroad.
Guidelines:
1. Clip the whole article if taken from a magazine or
newspaper. If it comes from the Internet, download the
whole article. If it is more than two pages, summarize
it.
2. Indicate the name of magazine/newspaper, date of
publication, title of article and author. Highlight the
population/sample/margin of error used in the article.
3. Identify statements which belong to: (a)descriptive
statistics (b) inferential statistics
4. Find out the population/sample used in the survey.
5. Enumerate the data gathered and classify whether they
are: a) qualitative b) quantitative

Basic Statistics

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Basic Statistics