Business Statistics: A Decision-Making Approach 7th Edition
Chapter 1 The Where, Why, and How of Data Collection
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-1
Perangkat pada Statistik
Statistik Deskriptif
Pengumpulan, penyajian, dan penjelasan data
Statistik Inferensial
Menggambarkan kesimpulan dan/atau membuat keputusan yang berkaitan dengan populasi berdasarkn hanya pd sample data
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-2
Statistik Deskriptif
Pengumpulan data
e.g., Survey, Observasi, Eksperimen
Penyajian data
e.g., Chart and grafik
Pengkarakteristikan data
x e.g., Rata2 sample =
i
n
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-3
Statistik Inferensial
Membuat pernyataan tentang populasi dengan memeriksa hasil dari sample
Sample statistics (diketahui)
Parameter population Inferensi (tdk diketahui, tetapi dapat diestimasi dr bukti sample)
Sample
Population
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-4
Statistik Inferensial Menggambarkan kesimpulan dan/atau membuat keputusan berdasarkan populasi berbasis pd hasil sample.
Estimasi e.g., Estimasi rerata bobot populasi menggunakan rerata bobot sample
Pengujian Hipotesis e.g., Menggunakan bukti sample utk menguji penyataan bahwa rerata bobot populasi adalah 120 pounds
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-5
Perangkat Pengumpulan Data Metode Pengumpulan Data
Eksperimen
Menulis kuestioner
Survey Telepon
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Observasi langsung dan wawancara personal
Chap 1-6
Langkah-langkah Disain Survey
Mendefinisikan isu
Apa maksud dan tujuan dari survey?
Mendefinisikan populasi yang dibutuhkan
Mengembangkan pertanyaan survey
Membuat pertanyaan yang jelas dan tdk ambigu
Menggunakan definisi yang umum dan dapat diterima
Membatasi jumlah pertanyaan
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-7
Langkah-langkah Disain Survey (continued)
Tes awal survey
Percobaan awal dengan jumlah sedikit partisipan
mengasess kejelasan dan rentangnya
Menentukan ukuran sample dan metode sampling
Memilih sample dan mengelola hasil survey
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-8
Tipe2 Pertanyaan
Pertanyaan Tertutup
Memilih short list definisi pilihan
Ex: Major: __business __liberal arts __science __other Pertanyaan Terbuka
Responden bebes memberikan to respond dengan nilai, katakata, atau statement
Ex: Apa baiknya dari kursus ini?
Pertanyaan Demograpi
Pertanyaan tentang karakteristik personal responden
Ex: Gender: __Female __ Male Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-9
Populasi dan Sample
Populasi adalah sekumpulan semua items or individual yang berkaitan
Examples:
Semua pemilik kendaraan Semua spare part yang diproduksi Semua sales receipts bulan November
Sample adalah subset dari populasi
Examples: 1000 pmilik kendaran yg dipilih secara acak sebagian parts yg diambil melaui teori peluang setiap 100th receipt dipilih utk audit
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-10
Definisi Kunci
population adalah
Suatu parameter adalah ukuran yg dihitung untuk menjelaskan karakteristik suatu populasi
sample adalah sebagian dari populasi yang dipilih untuk dianalisis
statistic adalah ukuran summary untuk menjelaskan karakteristik dari sample
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-11
Populasi vs. Sample Populasi a b
Sample
cd
b
ef gh i jk l m n o p q rs t u v w x y
z
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
c
gi o
n r
u
y
Chap 1-12
Mengapa Sample?
Less time consuming than a census
Less costly to administer than a census
It is possible to obtain statistical results of a sufficiently high precision based on samples.
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-13
Sampling Techniques Sampling Techniques
Nonstatistical Sampling Convenience
Statistical Sampling Simple Random
Systematic
Judgment Stratified Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Cluster
Chap 1-14
Statistical Sampling
Items of the sample are chosen based on known or calculable probabilities Statistical Sampling (Probability Sampling)
Simple Random
Stratified
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Systematic
Cluster
Chap 1-15
Simple Random Sampling
Setiap sampel yang mungkin memiliki kesempatan yang sama untuk dipilih
Pemilihan mungkin dengan pengembalian atau tanpa pengembalian
Sample dapat diperoleh menggunakan suatu table bilangan acak atau computer random number generator
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-16
Stratified Random Sampling
Divide population into subgroups (called strata) according to some common characteristic
Select a simple random sample from each subgroup
Combine samples from subgroups into one
Population Divided into 4 strata
Sample Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-17
Systematic Random Sampling
Decide on sample size: n
Divide frame of N individuals into groups of k individuals: k=N/n
Randomly select one individual from the 1st group
Select every kth individual thereafter N = 64 n=8
First Group
k=8 Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-18
Cluster Sampling
Divide population into several “clusters,” each representative of the population Select a simple random sample of clusters
All items in the selected clusters can be used, or items can be chosen from a cluster using another probability sampling technique
Population divided into 16 clusters.
Randomly selected clusters for sample
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-19
Data Types Data
Qualitative (Categorical)
Quantitative (Numerical)
Examples:
Marital Status Political Party Eye Color (Defined categories)
Discrete Examples:
Number of Children Defects per hour (Counted items)
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Continuous Examples:
Weight Voltage (Measured characteristics) Chap 1-20
Data Types
Time Series Data
Ordered data values observed over time
Cross Section Data
Data values observed at a fixed point in time
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-21
Data Types Sales (in $1000’s) 2003
2004
2005
2006
Atlanta
435
460
475
490
Boston
320
345
375
395
Cleveland
405
390
410
395
Denver
260
270
285
280
Time Series Data
Cross Section Data Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-22
Data Measurement Levels Measurements
Rankings Ordered Categories
Categorical Codes ID Numbers Category Names
Ratio/Interval Data
Ordinal Data
Nominal Data
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Highest Level Complete Analysis
Higher Level Mid-level Analysis
Lowest Level Basic Analysis
Chapter Summary
Reviewed key data collection methods
Introduced key definitions: Population vs. Sample
Primary vs. Secondary data types
Qualitative vs. Quanitative data
Time Series vs. Cross-Sectional data
Examined descriptive vs. inferential statistics
Described different sampling techniques
Reviewed data types and measurement levels
Business Statistics: A Decision-Making Approach, 7e © 2008 Prentice-Hall, Inc.
Chap 1-24
