• Statistics is derived from the Latin word "status" meaning state.

• Statistics is a collection of quantitative data, such as statistics of crimes, statistics of enrolment, statistics of unemployment.

• Statistics is also the study of how to collect, organize, analyze, and interpret numerical information from data.

2 Kinds of Statistics

1. Descriptive Statistics

2. Inferential Statistics

Descriptive Statistics - methods concerned with the collection, description, and analysis of a set of data without drawing conclusions of inferences about a larger set. Example:

1. A bowler wants to find his bowling average for past 12 games.

2. A housewife wants to determine the average weekly amount she spent on groceries in the past 3 months.

3. A politician wants to know the exact number of votes he received in the last election.

Inferential Statistics - methods concerned with making predictions or inferences about a larger set of data using only the information gather from a subset of this larger set Example:

1. A bowler wants to estimate his chance of winning a game based on his current season averages and the averages of his opponents

2. A housewife wants to predict based on last year’s grocery bills, the average weekly amount she will spend on groceries for this year.

3. A politician would like to estimate, based on an opinion poll, his chance of winning in the upcoming election.

4. As a recent cut-backs by the oil producing nation, we can expect the price of the gasoline to double in the next year.

DATA COLLECTION METHODS

1. Direct or Interview method - a person to person encounter between the interviewee and the interviewer.

• Interviewer - the one who gathers the information

• Interviewee - the source of information.

• Interview can be done personal, through phone or internet access.

2. Indirect or Questionnaire method - a technique in which questionnaire is used to elicit the information or data needed. The questionnaire is consist of questions printed or type in the definite order on a form or a set of forms.

3. Registration Method - obtains data from the records of the government agency authorized by law to keep such data or information and made these available to the researchers. Example: Birth and Death Rates – National Statistics Office (NSO) Number of Registered Cars – Land Transportation Office (LTO) List of Registered Voters – Commission on Elections ( COMELEC)

4. Observation Method - a technique in which data particularly those pertaining to the behaviors of individuals or group of individuals during the given situation are best describe through observation. Example:

   1. Observing the children’s behavior

   2. Observing the costumers movement

   3. Observing the traffic count

5. Experimental Methods - a system used to gather data from the results of performed series of experiments on same controlled and experimental variables. This is commonly used in scientific inquiries.

Types of Variable

1. Qualitative Variables describe a certain type of information without using numbers Examples: Color, Taste, Occupation, Gender and Preference to eating vegetables.

2. Quantitative Variables measure or identify an information using numeric scales Examples: Height, Number of Siblings, Speed of a car, Temperature, Number of students in a classroom, Amount of shirt in the drawer.

Classification of Quantitative Variable

1. Discrete Variable whose values can be counted using integral values. Examples: Number of Siblings , Number of students in a classroom, Amount of shirt in a drawer.

2. Continuous variable can assume any numerical value over an interval or intervals Examples: Height, speed of a car, temperature

Population - collection of all elements under consideration in a statistical study. ° A population data set contains all members of a specified group (the entire list of possible values) ° Totality of all the observations

Example:

1. All people living in the Philippines.

2. All students in CVSU.

Sample - A sample data set contains a part or a subset of a population. ° The size of the sample is always less than the size of the population from which it is taken. ° Subset of a population.

Example:

1. Some people living in the Philippines

2. Some students in CvSU

Parameter - numerical measurement describing some characteristics of a population Statistic - numerical measurement describing some characteristics of a sample Survey - conducted to gather opinions or feedback about a variety of topics

1. Census survey - conducted by gathering information from the entire population

2. Sampling survey - conducted by gathering information only from part of the population

LEVELS OF MEASUREMENT

1. Nominal

• Classificatory/Naming scale

• Characterized by data that consists of names, labels, or categories only.

Ex. name civil status gender religion address degree program

2. Ordinal

   1. Ranking scale

   2. The ordinal level of measurement contains the properties of nominal level, and in addition, the number assigned to categories of any variable maybe ranked or ordered in some low to high manner.

Example: Competition Placement Job position Year Level Level of Satisfaction Size of t-shirt

3. Interval

   1. An interval scale must have a common and constant unit of measurement.

   2. Furthermore, the unit of measurement is arbitrary and there is “no true zero point” .

Example: Temperature( in degree celcius and fahrenheit) IQ score SAT score

4. Ratio

• The ratio level of measurement contains all properties of the interval level and in addition, it has a

• '“true zero” point.**

Example:

Distance

Weight

Height

Weekly Allowance