BASIC TERMS USED IN STATISTICS

INTRODUCTION TO STATISTICS AND TERMS USED

WHAT IS STATISTICS ;

·         It is the science of data

·         It involves the collection, classification, summarization, organization and interpretation of numerical information and also entails the ability to effectively communicate and present the results and inference drawn from the data

POPULATION AND SAMPLE; A population is a chosen body of measurement or data, while the sample is a specified number of measurement or data. The sample is a subset of the population.

DESCRIPTIVE AND INFERENTIAL STATISTICS;

·         Descriptive statistics is a branch of statistics that deals with the description of a data set or measurement body, while inferential statistics is a branch of statistics that deals with the drawing of conclusions from a data set or measurement body based on a sample

·         Descriptive statistics consists of procedures used to summarize and describe important characteristics of a set of measurements, while inferential statistics consists of procedures used to draw inferences about the characteristics of a population based on a sample drawn from the population

·         Descriptive statistics makes use of NUMERICAL and GRAPHICAL methods to * describe patterns,* summarize information and * present information gotten from a data set, while inferential statistics makes use of SAMPLE DATA to make estimations, decisions, predictions and generalizations about a lager population

MEASUREMENT AND VARIABLE; Measurement is the process used to assign numbers to variables of a population unit, while a variable is a characteristic of a population unit. Variables changes over time for a population and or for different individuals or object under consideration.

          Variables can be grouped into

1.       Qualitative variables; they measure the quality or characteristic on each experimental unit. The data produced here can be used to categorise the variables based on similarities or differences and so can be called  categorical data. Eg; gender, year, department, political affiliation, performance level, color of a sweet

2.       Quantitative variables; they measure numerical quantity or amount on each experimental unit. They are of two types

DISCRETE; Which carry a finite value x= 0,1,2…..these are variables that can only assume a finite or countable number of values

CONTINUOUS; Which carry an infinite value 0<x infinity…..these are variables that can assume an infinite number of values corresponding to the points on a line interval.

GRAPHS USED FOR QUALITATIVE AND QUATITATIVE DATA (VARIABLE)

Since the qualitative variables deals with categorizing, then before chosing a graphical format of presentation there has to be a way of representing how often certain categories occur on the graph or statistical table. This is done by either using

·         The frequency or number of measurements in that category

·         The relative frequency or proportion of measurements in that category

·         The percentage of measurements in that category

FOR QUALITATIVE DATA; we usually use a pie chart and a bar chart

FOR QUANTITATIVE DATA; we usually use a pie chart, bar chart, histogram, line charts, dot charts

FEEL FREE TO ASK QUESTIONS OR MAKE CONTIBUTIONS BY POSTING IN THE COMMENT BOX. THANKS!!!