REVIEW IN STATISTICS

REVIEWER IN STATISTICS

Preparation for the Subject: Statistics and Probability for the Grade 11- Students

Prepared by: Mr. Jose Karlo Trocio

Introduction to Statistics

What is Statistics?

Statistics is a mathematical science including methods of collecting, organizing and analyzing data in such a way that meaningful conclusions can be drawn from them. In general, its investigations and analyses fall into two broad categories called descriptive statistics and inferential statistics.

Descriptive statistics

- deals with the processing of data without attempting to draw any inferences from it. The data are presented in the form of tables and graphs. The characteristics of the data are described in simple terms. Events that are dealt with include everyday happenings such as accidents, prices of goods, business, incomes, epidemics, sports data, population data.

Inferential statistics

- is a scientific discipline that uses mathematical tools to make forecasts and projections by analyzing the given data. This is of use to people employed in such fields as engineering, economics, biology, the social sciences, business, agriculture and communications.

Data is a body of information or observations being considered by researcher. When the data is processed, information , which is the basis for decision making is produced.

Variable is used to define certain observable values or characteristics. It is called variable since the characteristics vary from one another. The values of the variables are the possible observable values or characteristics of the variable. These values are the data to be processed. 

CLASSIFYING DATA

ACCORDING TO NATURE

Quantitative data (NUMERICAL) is data expressing a certain quantity, amount or range. Usually, there are measurement units associated with the data, e.g. metres, in the case of the height of a person.

Qualitative data (CATEGORICAL) is defined as the data that approximates and characterizes. Qualitative data can be observed and recorded. This data type is non-numerical in nature. This type of data is collected through methods of observations, interviews, etc. It is in the form of categories, characteristics, names or labels, e.g. gender, socio-economic status, civil status, etc. 

Multiple Select

The following are some items in a survey questionnaire. Mark check the data which can be classified as quantitative data. Do not mark check the qualitative data.

• Control number

• Marital Status

• Number of children

• Educational Attainment

• Occupation

Multiple Select

The following are some items in a survey questionnaire. Mark check the data which can be classified as quantitative data. Do not mark check the qualitative data.

• Average gross monthly income

• Years of service in the company

• Number of hours spent daily chatting online

• Number of glasses of water taken daily

Multiple Choice

Classify the data according to measurement / levels of data.

Nominal, Ordinal,Interval, Ratio.

ID number

• Nominal

• Ordinal

• Interval

• Ratio

CLASSIFYING DATA ACCORDING TO SOURCE

1.    Primary sources are original materials on which other research is based, including:

o   original written works – poems, diaries, court records, interviews, surveys, and original research/fieldwork, and

o   research published in scholarly/academic journals.

2.    Secondary sources are those that describe or analyze primary sources, including:

o   reference materials – dictionaries, encyclopedias, textbooks, and

o   books and articles that interpret, review, or synthesize original research/fieldwork.

ACCORDING TO ARRANGEMENT

 Grouped data is data that has been organized in classes after its analysis. Examples include how many bags of maize collected during the rainy season were bad.

 Ungrouped data is data which does not fall in any group. It is still raw data.