Transcript Chapter 20
Business Research Methods William G. Zikmund Chapter 20: Basic Data Analysis: Descriptive Statistics Copyright © 2000 by Harcourt, Inc. All rights reserved. Requests for permission to make copies of any part of the work should be mailed to the following address: Permissions Department, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando, Florida 32887-6777. Descriptive analysis • The transformation of raw data into a form that will make them easy to understand and interpret; rearranging, ordering, and manipulating data to generate descriptive information. Copyright © 2000 by Harcourt, Inc. All rights reserved. Type of Measurement Type of descriptive analysis Two categories Nominal More than two categories Frequency table Proportion (percentage) Frequency table Category proportions (percentages) Mode Copyright © 2000 by Harcourt, Inc. All rights reserved. Type of Measurement Type of descriptive analysis Ordinal Rank order Median Copyright © 2000 by Harcourt, Inc. All rights reserved. Type of Measurement Type of descriptive analysis Interval Arithmetic mean Copyright © 2000 by Harcourt, Inc. All rights reserved. Type of Measurement Ratio Type of descriptive analysis Index numbers Geometric mean Harmonic mean Copyright © 2000 by Harcourt, Inc. All rights reserved. Tabulation • Tabulation - Orderly arrangement of data in a table or other summary format • FREQUENCY TABLE • PERCENTAGES Copyright © 2000 by Harcourt, Inc. All rights reserved. Frequency table • The arrangement of statistical data in a rowand-column format that exhibits the count of responses or observations for each category assigned to a variable. Copyright © 2000 by Harcourt, Inc. All rights reserved. CENTRAL TENDENCY Type of Scale Nominal Ordinal Interval or ratio deviation Measure of Central Tendency Measure of Dispersion Mode Median Mean None Percentile Standard Copyright © 2000 by Harcourt, Inc. All rights reserved. Cross-tabulation • A technique for organizing data by groups, categories, or classes, thus facilitating comparisons; a joint frequency distribution of observations on two or more sets of variables. • Contingency table- The results of a crosstabulation of two variables, such as survey questions. Copyright © 2000 by Harcourt, Inc. All rights reserved. CROSS-TABULATION • ANALYZE DATA BY GROUPS OR CATEGORIES • COMPARE DIFFERENCES • CONTINGENCY TABLE • PERCENTAGE CROSS-TABULATIONS Copyright © 2000 by Harcourt, Inc. All rights reserved. Base • The number of respondents or observations (in a row or column) used as a basis for computing percentages. Copyright © 2000 by Harcourt, Inc. All rights reserved. ELABORATION AND REFINEMENT • MODERATOR VARIABLE – A third variable that, when introduced into an analysis, alters or has a contingent effect on the relationship between an independent variable and a dependent variable. – SPURIOUS RELATIONSHIP – An apparent relationship between two variables that is not authentic. Copyright © 2000 by Harcourt, Inc. All rights reserved. QUADRANT ANALYSIS Two rating scales 4 quadrants two-dimensional table ImportancePerformance Analysis) Copyright © 2000 by Harcourt, Inc. All rights reserved. DATA TRANSFORMATION • DATA CONVERSION • CHANGING THE ORIGINAL FORM OF THE DATA TO A NEW FORMAT • MORE APPROPRIATE DATA ANALYSIS • NEW VARIABLES Copyright © 2000 by Harcourt, Inc. All rights reserved. DATA TRANSFORMATION SUMMATIVE SCORE = VAR1 + VAR2 + VAR 3 Copyright © 2000 by Harcourt, Inc. All rights reserved. COLLAPSING A FIVE POINT SCALE • STRONGLY AGREE • AGREE • NEITHER AGREE OR DISAGREE • DISAGREE • STRONGLY DISAGREE • STRONGLY AGREE/AGREE • NEITHER AGREE OR DISAGREE • DISAGREE/ STRONGLY DISAGREE Copyright © 2000 by Harcourt, Inc. All rights reserved. INDEX NUMBERS • Score or observation recalibrated to indicate how it relates to a base number • CPI - Consumer Price Index Copyright © 2000 by Harcourt, Inc. All rights reserved. CALCULATING RANK ORDER • ORDINAL DATA • BRAND PREFERENCES Copyright © 2000 by Harcourt, Inc. All rights reserved. TABLES • BANNERHEADS FOR COLUMNS • STUDHEADS FOR ROWS Copyright © 2000 by Harcourt, Inc. All rights reserved. CHARTS AND GRAPHS • PIE CHARTS • LINE GRAPHS • BAR CHARTS – VERTICAL – HORIZONTAL Copyright © 2000 by Harcourt, Inc. All rights reserved. Copyright © 2000 by Harcourt, Inc. All rights reserved. Copyright © 2000 by Harcourt, Inc. All rights reserved. 100 80 60 East 40 W est 20 N orth 0 1st 2nd 3rd 4th Q tr Q tr Q tr Q tr Copyright © 2000 by Harcourt, Inc. All rights reserved. COMPUTER PROGRAMS • • • • SPSS SAS SYSTAT MICROSOFT EXCEL Copyright © 2000 by Harcourt, Inc. All rights reserved. COMPUTER PROGRAMS • Box and Whisker Plots • Interquartile range - midspread • Outlier Copyright © 2000 by Harcourt, Inc. All rights reserved. Interpretation • the process of making pertinent inferences and drawing conclusions • concerning the meaning and implications of a research investigation Copyright © 2000 by Harcourt, Inc. All rights reserved.