© 2002 Prentice-Hall, Inc.Chap 1-1 Bab 1 Pendahuluan

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-2 Topik Apa perlunya statistik ? Beberapa perkembangan statistik modern Konsep-konsep statistik Descriptive versus inferential statistics

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-3 Topik Kenapa data diperlukan Tipe dan sumber data Design of survey research Sampling methods Survey errors (continued)

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-4 Perkembangan Statistika Modern Adanya kebutuhan pemerintah Perkembangan Teory Probabilitas Matematika Kecanggihan Komputer

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-5 Definisi A population (universe) is the collection of things under consideration A sample is a portion of the population selected for analysis A parameter is a summary measure computed to describe a characteristic of the population A statistic is a summary measure computed to describe a characteristic of the sample

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-6 Population and Sample PopulationSample Use parameters to summarize features Use statistics to summarize features Inference on the population from the sample

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-7 Metode Statistika Descriptive statistics Collecting and describing data Inferential statistics Drawing conclusions and/or making decisions concerning a population based only on sample data

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-8 Descriptive Statistics Collect data e.g. Survey Present data e.g. Tables and graphs Characterize data e.g. Sample mean =

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-9 Inferential Statistics Estimation e.g.: Estimate the population mean weight using the sample mean weight Hypothesis testing e.g.: Test the claim that the population mean weight is 120 pounds Pengambilan keputusan tentang populasi berdasarkan hasil sample

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-10 Mengapa Data diperlukan ? survey study Pengukuran kinerja pelayanan atau proses production Mengevaluasi standar kepuasan Memformulasi beberapa alternatif kegiatan To satisfy curiosity

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-11 Sumber Data Primer Data Collection Sekunder Data Compilation Observation Experimentation Survey Print or Electronic

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-12 Tipe Data

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-13 Tipe Sampling Quota Samples Non-Probability Samples JudgementChunk Probability Samples Simple Random Systematic Stratified Cluster

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-14 Probability Sampling sampel dipilih berdasarkan nilai probabilitas Probability Samples Simple Random SystematicStratifiedCluster

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-15 Simple Random Samples Setiap anggota pada kerangka sampel mempunyai kesempatan yang sama untuk terpilih Pemilihan bebas Sampel dapat diperoleh dari tabel random atau generate dari komputer

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-16 Tergantung ukuran sampel : n frame of N individuals into groups of k individuals: k=n/n Randomly select one individual from the 1 st group Select every k-th individual thereafter Systematic Sampel N = 64 n = 8 k = 8 First Group

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-17 Stratified Samples Populasi dibagi ke dalam 2 atau lebih group tergantung karateristik Tiap group diambil secara Simple random sample

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-18 Cluster Samples Populasi dibagi dalam beberapa “clusters,” dengan karakteristik tertentu Tiap karaktristik, diambil sampel acak Population divided into 4 clusters.

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-19 Keuntungan dan Kerugian Simple random sample and systematic sample Mudah dilakukan Tidak bagus bagi populasi dengan karakteristik Stratified sample Bak bagi populasi yang beragam Cluster sample Biaya cukup mahal Kurang efisien (perlu ukuran sampel yang besar agar ketepatan sampel bagus)

Statistics for Managers using Excel, 3e © 2002 Prentice-Hall, Inc. Chap 1-20 Survey Errors Coverage error Non response error Sampling error Measurement error Excluded from frame. Follow up on non responses. Chance differences from sample to sample. Bad Question!