population vs sample

8/17/2019 Population vs Sample

1/30


2/30

Group MembersGroup Members

3575-FMS/BBA/F123575-FMS/BBA/F12





3/30

Population vs. SamplePopulation vs. Sample

Which one is better Which one is better


4/30

LayoutLayout

Introduction

Population and its typesSample

Types of samples

Conclusion


5/30

…the larger group from which

individuals are selected toparticipate in a study

PopulationPopulation


6/30

Cont...Cont...

The group of interest and itscharacteristics to which the findings of

the study will be generalized called the“targettarget” population (the ideal selection)

Oftentimes the “accessibleaccessible” or

“availableavailable” population must be used (therealistic selection)


7/30

The representatives selected for a

study whose characteristicsexemplify the larger group from

which they were selected

SampleSample


8/30

Approaches to quantitative sampling...Approaches to quantitative sampling...

. NonrandomNonrandom (Non-Probability)(Non-Probability)

!oes not have random sampling at any

state of the sample selection" increases

probability of sampling bias

1.1. !andom (Probability)!andom (Probability)

#llows a procedure governed by

chance to select the sample" controls

for sampling bias


9/30

Random sampling methods...Random sampling methods...

$ %tratified sampling&$ 'luster sampling

$ %ystematic sampling

$ %imple random sampling


10/30

1.1. Sim"l# random $am"lin%Sim"l# random $am"lin%

The process of selecting a sample thatallows individual in the defined

population to have an e*ual and

independent chance of being selected

for the sample


11/30

Advantages Advantages&

…easy to conduct

…strategy re*uires minimum +nowledge

of the population to be sampled


12/30

Disadvantages Disadvantages&

…need names of all population members

…may over, represent or under,

estimate sample members

…there is difficulty in reaching all

selected in the sample


13/30

$ Strati'i#d $am"lin%Strati'i#d $am"lin%

The process of selecting a sample thatallows identified subgroups in the

defined population to be represented

in the same proportion that they exist

in the population


14/30


…more precise sample…can be used for both proportions and

stratification sampling

…sample represents the desired strata


15/30


…need names of all population members…there is difficulty in reaching all

selected in the sample

…researcher must have names of allpopulations


16/30

3. l$t#r $am"lin%l$t#r $am"lin%

The process of randomly selectingintact groups- not individualswithin

the defined population sharing similar

characteristics


17/30


…efficient…researcher doesn.t need names of all

population members

…reduces travel to site…useful for educational research


18/30


…fewer sampling points ma+e it lessli+e that the sample is

representative


19/30

*. Sy$t#mati+ $am"lin%Sy$t#mati+ $am"lin%

The process of selecting individualswithin the defined population from a list

by ta+ing every K K th name$


20/30


…sample selection is simple


21/30


…all members of the population do nothave an e*ual chance of being selected

…the K K th person may be related to a

periodical order in the population list-producing unrepresentativeness in the

sample


22/30

onrandom sampling methods... onrandom sampling methods...

$ /urposive sampling&$ 0uota sampling

$ 'onvenience sampling


23/30

1.1. on,#ni#n+# $am"lin%on,#ni#n+# $am"lin%

The process of including whoeverhappens to be available at the time

…also called “accidental” or

“haphazard” sampling


24/30


…difficulty in determining how much ofthe effect (dependent variable) results

from the cause (independent variable)


25/30

2. Pr"o$i,# $am"lin%Pr"o$i,# $am"lin%

The process whereby the researcherselects a sample based on experience

or +nowledge of the group to be

sampled

…also called “1udgment” sampling


26/30


…potential for inaccuracy in theresearcher.s criteria and resulting

sample selections


27/30

3. ota $am"lin%ota $am"lin%

The process whereby a researchergathers data from individuals

possessing identified characteristics

and *uotas


28/30


…people who are less accessible (moredifficult to contact- more reluctant to

participate) are under,represented


29/30

ConclusioConclusionn


30/30

population vs sample

Documents