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Statistics and Probability

STATISTICS – deals with the collection, organization, presentation, analysis and interpretation of numerical data used as information for decision making. Descriptive Statistics – is a field of statistics that does not involve any generalization. Branch of science that deals with the methods concerned with the collection and description of data .This includes any thing done to the data that is designed to summarize or describe it without attempting to infer anything that goes beyond it.

Inferential Statistics- makes use of generalizations, predictions, estimations or approximations in the face of uncertainty .

Methods of Collecting Data1.Direct method- data is collected through the use of

interviews. The enumerator talks to the subject personally. He gets the data through a series of questions asked from the subject of the interview.

2.Indirect method- data is collected through the use of questionnaires.

3.Observation- Information is gathered by recording the behavior , attitude , or attribute of items, persons or group of items or persons at the time of occurrence.

Methods of Collecting Data4.) Experimentation-data is usually gathered through experiments in laboratories and classrooms.5.) Registration-data are acquired from private and government agencies such as from the National Statistics Office, the Bangko Sentral ng Pilipinas, Department of Finance, etc.

Ways in Presenting Data

1.Textual form- data and information are presented in paragraph and narrative form.

2. Tabular form- Quantitative data are summarized in rows and columns.

3.Graphical form- data are presented in charts, graphs or pictures.

Year Level Number of Students First Year 35

Second Year 50

Third Year 48

Fourth Year 24

Population and Sample

Population- is a set of all data tat characterizes some phenomenon of interest. That is, the totality or collection of all elements to be studied. The population is also the universe set..

Sample – is a representative portion of the population

Variable –is a characteristics that changes or varies over time and for different individuals or objects under consideration.Quantitative and Qualitative Variable

Quantitative variable- measures a characteristics on each individual or object

Quantitative variable-measure a numerical amount on each individual or objects

Discrete and Continuous Variable

Discrete variable- can assume only a finite or countable number of values.

Continuous variable- can assume an infinite number of values corresponding to the point on a line interval.

Measurement Scales

1.) nominal level -the first level of measurements that consists of names, labels or categories only in which no order or ranking can be imposed. Example: Gender (male and female ), Marital Status (single, married, separated) ,employment (business, construction, engineering, education and etc. )2.) ordinal level- data measured can be ordered or rank but precise differences do not exist. Example : Income Distribution (low income, middle income and upper income), Body build (small, medium ,large)

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Measurement Scales

3.) interval level –consist of data that may be arranged and meaningful amount of differences between data values can be determined, however, there is no meaningful zero. Example: Temperature, score in a particular examination4.) ratio level- consist of data tat ma be arranged and meaningful amounts of differences between data values can be determined and ratios between data values are meaningful. Example :Weight, Height, Age

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Determine which level is most appropriate in measuring each of the following data.

1. SSS number2. Weight of a package3. Size of a family4. t-shirt size (small, medium, large, extra large)5. religion6. Speed of a car in km/hr7. SASE rating.

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Data

Qualitative Quantitative

Discrete Continuous

Nominal Ordinal Interval Ratio

Percentages - is the number of hundredth parts one number is of another. The percent which the given number is of the base may be defined as:

Where represents the number of parts of 100 represents the based used in the comparison represents the given data to be compared with the base

Example :

Out of 4,000 LCD screens produced by Pansonic Electronic Company, 40 are defective. What is the percentage of defective television produced by the company?

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