market research descriptive statistics

coding

process of grouping and assigning numeric codes to various responses to question

data entry

process of converting information to electronic format

after collecting data, what next?

data editing

coding

statistically adjusting data

data editing

identifies omissions, ambiguities, and errors in responses

problems identified with data editing

interviewer error

omissions

ambiguity

inconsistencies

coding

closed ended questions involves specifying how responses are to be entered

assigning numeric value to responses

open ended questions are difficult to ____

• lengthy list of possible responses is generated

mean

average

median

score in middle

order values from small to large

measures for dispersion

describe spread of data or variation around the mean

variance

average squared difference

standard deviation

square root of variance

range

largest val - smallest val

continuous variable

subject or observation takes value from interval of real numbers. for example, if weight can be measured preciseley enough it takes any value from 0 upwards

discrete or categorical variable

subjects or observations can be categorized. for example, vote choice is discrete variable since there is limited set of parties or candidates to vote for

you cannot report means, std deviations, etc for ______ & _____ variables

nominal

ordinal

nominal & ordinal

proportions (= percentages), counts, or frequency tables

interval and ratio scales

mean, median, sd, variance, range

descriptive statistics

make data usable

describe results from survey

inferential statistics

generalize results to a population

managerial decisions: are for population, not sample

population parameters

summary descriptions f variables of population

parameter denotes ‘ true value’ from census rather than sample

sample statistic

summary description of variable of sample

used as estimate for population parameter

how can data be summarized? descriptive statistics

1. numerical summaries

   1. central tendency (mean, median)

   2. measure if dispersion

2. graphical summaries

   1. frequency distribution

   2. histogram

   3. charts

nominal and ordinal graph

frequency tables, bar chart, pie chart

interval and ratio graph

histogram