1

Pertemuan KesembilanSampling and Data Collection

Matakuliah : MN J0412/ Riset Pemasaran

Tahun : 2007

Versi :

2

Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa

akan mampu :

• Mahasiswa dapat menyisihkan sampel dan populasi tanpa menghilangkan unsur

3

Outline Materi

• Materi 1: Required Steps in Sampling

• Materi 2: Types of Sampling Plans

• Materi 3: Non Probability Samples

• Materi 4:Probability Samples

• Materi 5: Sample Size

4

6-Step Procedure for Drawing a Sample

Define the Target Population

Identify the Sampling Frame

Select a Sampling Procedure

Determine the Sample Size

Select the Sample Elements

Collect the Data from the Designated Elements

Step 1

Step 2

Step 4

Step 3

Step 5

Step 6

5

Classification of Sampling Techniques

Sampling Designs

Nonprobability Samples•Convenience•Judgment•Quota

Probability Samples•Simple Random•Statified

•Proportionate•Disproportionate

•Cluster•Systematic•Area

6

Distribution of Sample Means for Different Samples Sizes, Population Shapes

n = 2

Populations

n = 5

Sampling

Distributions

of mean

n = 30

7

Relationship Between Parameters of Parent Population and Derived Population

A

B

C

D

E

F

Element

Total

Parent Population

3

6

9

12

15

18

Mean:

3 + 6 + 9 + 12 + 15 + 18

6

Xi

N

Variance: 2

(Xi-)2 (3-10.5)2 + ... +(18-10.5)2

N6

= 157.5 = 26.256

=

=

=

=

= 10.5

8

Derived Population of All Possible Distinguishable Samples

1 2 3 4 5 6 7 8 91011121314151617181920

ABCABDABEABFACDACEACFADEADFAEFBCDBCEBCFBDEBDFBEFCDECDFCEFDEF

1821242724273030333627303333363936394245

6 7 8 9 8 910101112 9101111121312131415

Element Total Mean Xj

9

Derived Population

Mean:

=(6 -10.5)2 + (7-10.5)2 + ... + (15-10.5)2 2

0

Variance: 2

= 5.25

E( x ) x

L xj

j =1 L

6 + 7 + ... + 15 105

L ( xj

j =1 L

- E(x))2

20 20== = = 10.

5

=_x

10

Distribution of Variables in Parent and Derived Population

1 3 5 7 9 11 13 15 17

1 3 5 7 9 11 13 15 17

1

0

1

0

2

3

Values of x

Values of X

AbsoluteFrequency

AbsoluteFrequency

11

Example Calculations of Generating a Confidence Interval with a Stratified Sample

I II

III IV

n1 = 100

x1 = Xi1 = 3.2n1

x1 )2 (Xi1 = .14n1 -1

s12 = ^

n3 = 100

x3 = Xi3 = 5.8n3

x3 )2 (Xi3 = .20n3 -1

s32 = ^

n4 = 100

x4 = Xi4 = 7.2n4

x4 )2 (Xi4 = .18n4 -1

s42 = ^

n2 = 100

x2 = Xi2 = 4.6n2

x2 )2 (Xi2 = .12n2-1

s22 = ^

12

Size and Strata in Parent Population

N1 =

N2 =N3 =N4 =

N = 50000

xst =

= 1/10(3.2) + 5/10(4.6) + 3/10(5.8) + 1/10(7.2) = 5.08

= (1/10)2 (.14) + (5/10)2 (.12) + (3/10)2 (.20)100 100 100

+ (1/10)2 (.18) = .00051210

0

=.0226

Nhxh

NL

h=1Whxh

L

h=1

sxst

= L

h=1

Whs2xh =

Nh

N

2 (sh)2

nh

^

L

h=1

2sxst

=

I.

II.

III.

IV.

5000

25000

15000

5000

( )