1. Definition of Statistics
TEACHING BASIC STATISTICS ….
Definition of Statistics
A branch of mathematics dealing with the collection, analysis, interpretation, and presentation of masses of numerical data

2. TEACHING BASIC STATISTICS ….
History of Statistics
The term statistics came from the Latin phrase “ratio status” which means study of practical politics or the statesman’s art.
In the middle of 18th century, the term statistik (a term due to Achenwall) was used, a German term defined as “the political science of several countries”
From statistik it became statistics defined as a statement in figures and facts of the present condition of a state.

3. Application of Statistics
TEACHING BASIC STATISTICS ….
Application of Statistics
Comparing the effects of five kinds of fertilizers on the yield of a particular variety of corn
Determining the income distribution of Filipino families
Comparing the effectiveness of two diet programs
Prediction of daily temperatures
Evaluation of student performance

4. Two Areas of Statistics
TEACHING BASIC STATISTICS ….
Two Areas of Statistics
Statistics aims to uncover structure in data, to explain variation…
Descriptive
Inferential

5. TEACHING BASIC STATISTICS ….
Areas of Statistics
Inferential statistics
methods concerned with the analysis of a subset of data leading to predictions or inferences about the entire set of data
Descriptive statistics
methods concerned w/ collecting, describing, and analyzing a set of data without drawing conclusions (or inferences) about a large group

6. Example of Descriptive Statistics
TEACHING BASIC STATISTICS ….
Example of Descriptive Statistics
Present the Philippine population by constructing a graph indicating the total number of Filipinos counted during the last census by age group and gender

7. Descriptive Statistics
TEACHING BASIC STATISTICS ….
Descriptive Statistics
Descriptive statistics merely “describes” research and does not allow for conclusions or predictions.
Descriptive statistics usually operates within a specific area that contains the entire target population.

8. Example of Inferential Statistics
TEACHING BASIC STATISTICS ….
Example of Inferential Statistics
A new milk formulation designed to improve the psychomotor development of infants was tested on randomly selected infants.
Based on the results, it was concluded that the new milk formulation is effective in improving the psychomotor development of infants.

9. Inferential Statistics
TEACHING BASIC STATISTICS ….
Inferential Statistics
Inferential statistics makes it possible for the researcher to arrive at a conclusion and predict changes that may occur regarding the area of concern.
Inferential statistics usually takes a sample of a population, especially if the population is too large to conduct research on.

10. Descriptive or Inferential?
TEACHING BASIC STATISTICS ….
Descriptive or Inferential?
The average age of the students in Grade 11 is 17 years.
2. The Internet remains inaccessible to seven out of 10 Filipinos
3. Henry averaged 2 new car sold for the last 3 weeks.
4. Michael Jordan played six NBA Finals in his 15-year career.
5. From past figures, it is predicted that 79% of the registered voters in QC will vote in the Presidential election.

11. Introduction to Basic Terms
TEACHING BASIC STATISTICS ….
Introduction to Basic Terms
Population: A collection, or set, of individuals or objects or events whose properties are to be analyzed.
Sample: A subset of the population.

12. TEACHING BASIC STATISTICS ….
Basic Terms
Parameters are numerical measures that describe the population or universe of interest. Usually donated by Greek letters;  (mu),  (sigma),  (rho),  (lambda),  (tau),  (theta),  (alpha) and  (beta).
Statistics are numerical measures of a sample

13. Parameters vs. Statistics
TEACHING BASIC STATISTICS ….
Parameters vs. Statistics

14. Parameters or Statistics?
TEACHING BASIC STATISTICS ….
Parameters or Statistics?
A recent survey by the alumni of a major university indicated that the average salary of 10,000 of its 300,000 graduates was Php 25,000.
The average salary of all employees at UST-Angelicum is Php 33,000.
In New York City, there are 3250 walk buttons that the pedestrians can press at traffic intersections. It was found that 77% of those buttons do not work.

15. TEACHING BASIC STATISTICS ….
Basic Terms
Variable: A characteristic about each individual element of a population or sample.
Data (singular): The value of the variable associated with one element of a population or sample. This value may be a number, a word, or a symbol.
Data (plural): The set of values collected for the variable from each of the elements belonging to the sample.

16. TEACHING BASIC STATISTICS ….
Types of Variables
Qualitative variable
A variable that categorizes or describes an element of a population.
Quantitative variable
A variable that quantifies an element of a population.

17. Qualitative or Quantitative?
TEACHING BASIC STATISTICS ….
Qualitative or Quantitative?
Example: Identify each of the following examples as attribute (qualitative) or numerical (quantitative) variables.
1. The residence hall for each student in a statistics class.
2. The amount of gasoline pumped by the next 10 customers at the local Unimart.
3. The amount of radon in the basement of each of 25 homes in a new development.
4. The color of the baseball cap worn by each of 20 students.
5. The length of time to complete a mathematics homework assignment.
6. The age of your car.
7. The state in which each truck is registered when stopped and inspected at a weigh station.

18. TEACHING BASIC STATISTICS ….
Levels of Measurement
Nominal
Numbers or symbols used to classify
Ordinal scale
Accounts for order; no indication of distance between positions
Interval scale
Equal intervals; no absolute zero
Ratio scale
Has absolute zero

19. TEACHING BASIC STATISTICS ….
Discrete Variable: A quantitative variable that can assume a countable number of values. Intuitively, a discrete variable can assume values corresponding to isolated points along a line interval. That is, there is a gap between any two values.
Continuous Variable: A quantitative variable that can assume an uncountable number of values. Intuitively, a continuous variable can assume any value along a line interval, including every possible value between any two values.

20. TEACHING BASIC STATISTICS ….
Discrete or Continous?
1. The temperature in Baguio at 12:00 pm on any given day. 2. The make of automobile driven by each faculty member. 3. The number of chairs in the room 4. The weight of a lead pencil. 5. The length of time billed for a long distance telephone call. 6. The brand of cereal children eat for breakfast. 7. The type of book taken out of the library by an adult. 8. The price of gasoline.

21. TEACHING BASIC STATISTICS ….
Levels of Measurement
Nominal
Numbers or symbols used to classify
Ordinal scale
Accounts for order; no indication of distance between positions
Interval scale
Equal intervals; no absolute zero
Ratio scale
Has absolute zero

22. Levels of Measurement
1. A nominal scale is an unordered set of categories identified only by name. Nominal measurements only permit you to determine whether two individuals are the same or different. (Religious Preference, Political Orientation, Meal Preference)
2. An ordinal scale is an ordered set of categories. Ordinal measurements tell you the direction of difference between two individuals. (Grade Levels, Military Ranking, Race Results)

23. Levels of Measurement
An interval scale is an ordered series of equal-sized categories. Interval measurements identify the direction and magnitude of a difference. The zero point is located arbitrarily on an interval scale.
(Temperature, IQ Level, Military Time)
4. A ratio scale is an interval scale where a value of zero indicates none of the variable. Ratio measurements identify the direction and magnitude of differences and allow ratio comparisons of measurements. (Years of Work Experience, Income, Number of Children)

24. TEACHING BASIC STATISTICS ….
Levels of Measurement
1. The length of time until a pain reliever begins to work.
2. The number of chocolate chips in a cookie.
3. The number of colors used in a statistics textbook.
4. The brand of refrigerator in a home.
5. The overall satisfaction rating of a new car.
6. The number of files on a computer’s hard disk.
7. The pH level of the water in a swimming pool.
8. The number of staples in a stapler.

25. TEACHING BASIC STATISTICS ….
10. Hair color of women on a high school tennis team
11. Numbers on the shirts of a girl’s soccer team
12. Ages of students in a statistics class
13. Temperatures of 22 selected refrigerators
14. Number of milligrams of tar in 28 cigarettes
15. Number of pages in your statistics book
16. Marriage status of the faculty at the local community college
17. List of 1247 social security numbers
18. The ratings of a movie ranging from “poor” to “good” to “excellent”
19. The final grades (A,B,C,D, and F) for students in a chemistry class
20. The annual salaries for all teachers in Utah