Basic Concepts II-Statistics-Lecture Slides, Slides of Statistics

Download Basic Concepts II-Statistics-Lecture Slides and more Slides Statistics in PDF only on Docsity!

Statistics:

1. Facts or data of a numerical kind,assembled, classified and tabulatedso as to represent significantinformation about a given subject

2. Science of assembling, classifyingand tabulating such facts or data. Subject

deals with

scientific

methods of collecting, organizing,summarizing, presenting andanalyzing + Drawing valid conclusions and makingreasonable decisions on the basis ofsuch analysis

Descriptive Statistics

Consists of methods of organizingand summarizing information.(Describe informations)

E.g. Mean blood pressure of a group ofpatients Ratio of male to female alcoholics. Cricket record of Pakistan cricket teametc.

This refers only to actual numbersand data available and includes theconstruction of graphs, charts andtables and calculations of variousdescription means such as averages,measure of dispersion and percentiles

Basic Concepts

Population

:- The collection of all

individuals, items or data underconsideration in a statistical study(Examples) Sample

:- The part of population from

which information is collected

Sample

population

Population refers to observationrelated to the patients If an investigator wants to know theplasma level of a drug in a group ofpatients. Population

patient plasma

level not patients Sample

sub set of population

The part that is actually being studiedor observed.

Basic concepts (contd)

Data ~ collective information aboutsome events. Qualitative data ~ white, high, low etc Quantitative data ~ expressed in no.(Numerical data)

Nominal data that take on one of two

distinct values—such as male andfemale– are said to be dichotomousor binary data Blood Group

1 - O2 - A3 - B4 - AB

Ordinal dataWhen order becomes important.The observations are referred to as ordinal

data Exp Injuries can be classified according to

level of severity 1-fatal2-severe3-moderate4-minorArithmetic operations do not make sense

when applied to ordinal data

Rank

Cause of Death

Total deaths

1

Disease of Heart

717706

2

Malignant neoplasms

620578

3

Cerebrovascular diseases

143769

4

Chronic obstructive pulmonarydiseases

91938

5

Accidents and adverse effects

86777

6

Pneumonia and influenza

75719

7

Diabetes mellitus

50067

8

Human immunodeficiency virusinfection

33566

9

Suicide

30484

10

Homicide and legal intervention

25488

Discrete data^ Both ordering and magnitude are important

.

In this case, the numbers represent actual

measurable quantities rather than merelabels. In addition, discrete data arerestricted to taking on only specifiedvalues– often integers or counts– that differby fixed amounts; no intermediate valuesare possible. Examples of discrete datainclude the number of motor vehicleaccidents in Massachusetts in a specifiedmonth, the number of times a woman hasgiven birth, the number of new cases oftuberculosis reported in the united statesduring a one-year period, and the numberof beds available in a particular hospital.

Raw data:- The collected data whichhas not been organized numerically(unprocessed) Variable:- A measurablecharacteristics which can assumedifferent values. (any quantity/ qualityliable to show variation from oneindividual to next in the samepopulation) Variable ~ continuous/discrete

Array:- The arranged data inascending or descending order. Range:- It is the difference betweenthe smallest and the largest numberin an array. Census/survey:- The collection,tabulation and interpretation ofvarious aspects of data based onobservation or measurements ofwhole population

Census

A selected sample

Survey