Statistik Deskriptif

METODE STATISTIK

Pendahuluan

© 2002 Prentice-Hall, Inc. Chap 1-1

Mengapa Perlu Statistik?

 Untuk mengetahui informasi yang
tepat

 Untuk membuat keputusan yang tepat
berdasarkan informasi sampel

 Mempercepat proses pengambilan
keputusan

 Mendapatkan peramalan yang valid

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-2

Metode Statistik

 Statistik Deskriptif

 Pengumpulan dan mendeskripsikan data

 Statistik Inferensi

 Membuat kesimpulan atau keputusan untuk
populasi berdasarkan sampel data

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-3

Statisitk Deskriptif

 Pengumpulan data

 Contoh, Survey

 Presentasi data

 Contoh, Tabel dan Grafik

 Karakteristik data  Xi

 Contoh. Nilai rata-rata = n

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-4

Statistik Inferensi

 Estimasi

 Contoh. Estimasi nilai rata-
rata populasi menggunakan
nilai rata-rata sampel

 Pengujian Hipotesis

 Contoh. Menguji bahwa berat
badan populasi adalah 50 kg

Drawing conclusions and/or making decisions
concerning a population based on sample results.

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-5

Data Sources

Primary Secondary

Data Collection Data Compilation

Observation Print or Electronic
Survey

Experimentation

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-6

Types of Data

Data

Categorical Numerical
(Qualitative) (Quantitative)

Discrete Continuous

Basic Business Statistics, 8e © 2002 Prentice-Hall, Inc. Chap 1-7

METODE STATISTIK

Presentasi Data Kedalam Tabel
dan Diagram

© 2002 Prentice-Hall, Inc. Chap 2-8

Tabulating and Graphing
Numerical Data

Numerical Data 41, 24, 32, 26, 27, 27, 30, 24, 38, 21

Ordered Array Frequency Distributions Ogive

21, 24, 24, 26, 27, 27, 30, 32, 38, 41 Cumulative Distributions 120
100

80

60

40

20

0

10 20 30 40 50 60

Stem and Leaf 2 144677 Histograms Ogive
Display
3 028 7
41 Tables 6 Polygons
5
4
3
2
1
0

10 20 30 40 50 60

© 2002 Prentice-Hall, Inc. Chap 2-9

Tabulating and Graphing
Categorical Data:Univariate Data

Categorical Data

Tabulating Data Graphing Data
The Summary Table
Pie Charts
© 2002 Prentice-Hall, Inc. Bar Charts Pareto Diagram

Chap 2-10

“Chart Junk”

Bad Presentation  Good Presentation

Minimum Wage Minimum Wage
1960: $1.00
1970: $1.60 4$
1980: $3.10
2
1990: $3.80
0
1960 1970 1980 1990

© 2002 Prentice-Hall, Inc. Chap 2-11

No Relative Basis

Bad Presentation  Good Presentation
A’s received by
A’s received by
30 % students.
Freq. students.

300 10
200

 FR SO JR SR

0
FR SO JR SR

FR = Freshmen, SO = Sophomore, JR = Junior, SR = Senior

© 2002 Prentice-Hall, Inc. Chap 2-12

Compressing Vertical Axis

Bad Presentation Good Presentation

Quarterly Sales Quarterly Sales

200 $ 50 $

100 25

0 0
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

© 2002 Prentice-Hall, Inc. Chap 2-13

No Zero Point on Vertical Axis

Bad Presentation  Good Presentation
Monthly Sales
$ Monthly Sales $
45
45 42
42 39
39 36
36
0
J F M A MJ J FM AM J

Graphing the first six months of sales. Chap 2-14

© 2002 Prentice-Hall, Inc.

TERIMA KASIH