�ݺ�ߣ

• Statistics is a ‘numbers game’
• Application of common sense to the
numerical facts of life
• Better position to act in the face of
uncertainty- risks

• The objective of Statistics is to make
inferences (predictions, decisions) about a
population based upon information contained
in a sample.
• Mendenhall

Statistics
Two meanings
* Specific numbers
* Method of analysis

Statistics
• Specific number
• Numerical measurement determined by a set of data
• Example: Thirty three percent of people
polled believed that present eudcation
system is good

• Number of trained community health
workers in the different districts of the
country
• Birth weight of the babies
• Amount of creatinine in mg per litre ina 24-
hour urine specimen
Statistics……

 Method of analysis
a collection of methods for planning
experiments, obtaining data, and
then organizing, summarizing, presenting,
analyzing, interpreting, and drawing
conclusions based on the data
Statistics

• Collection of data on participants in
a disease intervention programme
• Collection of data to compare the
relative effects of two drugs

Definition-Statistics
• means an aggregate of facts
• are affected to a marked extent by
multiplicity of causes
• Numerically expressed
• Are enumerated or estimated according to
reasonable standards of accuracy
• Collected in a systematic manner
• Collected for a predetermined purpose
• Are placed in relation to each other

What is Meant by Statistics?





Statistics is the science
of collecting, organizing,
presenting, analyzing,
and interpreting
numerical data to assist
in making more
effective decisions.

Definitions
Population
the complete collection of all
elements (scores, people,
measurements, and so on) to be
studied. The collection is complete
in the sense that it includes all
subjects to be studied.

Definitions
Census
the collection of data from every
element in a population
Sample
a subcollection of elements drawn
from a population

 Parameter
a numerical measurement describing
some characteristic of a population
Definitions

 Parameter
some characteristic of a
population
population
parameter
Definitions

Definitions
Statistic
some characteristic of a sample

Definitions
Statistic
some characteristic of a sample
sample
statistic

Definitions
Quantitative data
numbers representing counts or
measurements

Definitions
Quantitative data
Measurable value - Height, Weight …..
 Qualitative (or categorical or
attribute) data
can be separated into different categories that are
distinguished by some nonnumeric characteristics
Eg: Gender , Religion, education status…

Quantitative data:
Discrete
data result when the number of possible values is either a
finite number or a ‘countable’ number of possible values
0, 1, 2, 3, . . .
Continuous
(numerical) data result from infinitely many possible
values that correspond to some continuous scale that
covers a range of values without gaps, interruptions, or
jumps
Definitions

 Discrete
The number of children in a class room
 Then number of patients in Ward A
 Measurement like SBP, DBP, Pulse rate.
Continuous
The height of students
The weight of students
Skin fold thickness …..
Definitions

Q ualitative or attribute
(type of car owned)
discrete
(num ber of children)
continuous
(tim e taken for an exam )
Q uantitative or num erical
DATA

 nominal level of measurement
characterized by data that consist of names, labels, or
categories only. The data cannot be arranged in an
ordering scheme (such as low to high)
• Example: Nominal scale
– Eye color: Blue, green, or brown
– No rank or order to the categories
– Presence or absence of a disease
– Gender
Definitions

 ordinal level of measurement
involves data that may be arranged in some order, but
differences between data values either cannot be
determined or are meaningless
Example: Course grades A, B, C, D, or F
Mild, moderate, severe
Definitions

– Ordinal scale
–All the characteristics of a nominal scale,
plus there is a ranking among the categories:
–e.g., Mild, Moderate, Severe;
–First place, Second place, Third place
–Strongly Agree - - - - Strongly Disagree

Measurement Scales
• Quantitative scales
– Interval scale
• Designates an equal-interval ordering
• No true zero point
• The distance between 1 and 2 is the same as
the distance between 49 and 50
–Fahrenheit temperature scale: 0 F does not
mean no temperature
–60 degrees F is not twice as warm as 30
degrees

 interval level of measurement
like the ordinal level, with the additional property that the
difference between any two data values is meaningful.
However, there is no natural zero starting point (where
none of the quantity is present)
Example: Temperature
Definitions

 ratio level of measurement
the interval level modified to include the natural zero
starting point (where zero indicates that none of the
quantity is present). For values at this level, differences
and ratios are meaningful.
Example: Height, weight….
Definitions

Levels of Measurement
 Nominal - categories only
 Ordinal - categories with some order
 Interval - differences but no natural starting
point
 Ratio - differences and a natural starting point

Two phases of statistics:
Descriptive Statistics:
Describes the characteristics of a product or
process using information collected on it.
Inferential Statistics (Inductive):
Draws conclusions on unknown process
parameters based on information contained in
a sample.
Uses probability

FUNCTIONS OF STATISTICS
• To Compare
• To find the association
• To find the correlation
• To predict
• To find the reliablility & Validity

�ݺ�ߣ

1statistics research methodology ...pptx

Recommended

More Related Content

Similar to 1statistics research methodology ...pptx (20)

More from Snehamurali18 (20)

Recently uploaded (20)

1statistics research methodology ...pptx

Editor's Notes