Statistics

Statistics
 
Refers to the method applied in manipulating data to make it more meaningful. This includes the process of collection, organization, analysis and interpretation of the result of the analysis in order to draw conclusions that would be of great help in decision-making.

Divisions of Statistics
-deals with procedures that organize, summarize and describe quantitative data. It involves tabulating the data into various categories and indicating the quantities and percentages corresponding to each category. It includes graphs, averages and standard deviations to describe some of the features of the population.

Inferential Statistics
 -is a scientific discipline concerned with the developing and using mathematical tools to make forecasts and judgement or conclusion about a population based on the study of the sample that is taken from the population.

Some Uses of Statistics
1. Explore the characteristics of a large group of items on the basis of a few.
2. In politics: Find disposition of voters toward a certain candidate.
3. In business: For a retailer who is interested whether the bolts in a large shipment are within specifications. Advertising agencies might be interested in consumer preferences in hair shampoos.
4. In Manufacturing Industry: Quality control division is interested to find out the life span of electric bulbs produced.
5. In education: The dean of the college might be interested to find out the academic performance predictive value of its entrance test.

Basic Terms in Statistics

1. Variable- is a quantity that may assure any set of values. Ex. Math Grade, average grade, monthly income, price, harvest per hectare, etc.
2. Constant- a quantity that does not change its value. Ex: 1 meter = 3.28 ft, etc.
3. Ungrouped(or raw) Data- data which are not organized systematically. They are simply the collection of data as they are gathered.
4. Array- arrangement of data in an ascending or descending order.
5. Grouped Data- are raw data organized into groups or categories with corresponding frequencies. Data organized is referred to as Frequency Distribution.
6. Population- is the group/subject/focus of research or study. It is the entire collection of all conceivable observations of a particular characteristics of  sample.
7.  Sample- is a fraction of the population carefully taken as to be truly representative of the population. It reflects the characteristic of the whole population.
8. Parameter- any quantitative measure that describes a characteristic/feature of the population. Parameters are constant peculiar to a given population.
9. Statistic- a quantitative measure that describes a characteristic of a sample.
10. Qualitative Variable- a feature of the subjects under study identified simply by noting its presence. It enables the researcher to classify the subjects into groups  and each group is given an identify mark or name. Some ex: color of the eye, gender, and outcomes of tossing a coin. It is possible to assign numerical values to a quantitative value.
11. Quantitative variable- consists of numerical values. Ex: Heights of students in a certain school, waiting time at a bus stop, volume of sales in a day. Some quantitative variables may be regrouped and given names and become qualitative variables.