Module 2Descriptive StatisticsSummarizing Qualitative DataSummarizing Quantitative DataExploratory Data AnalysisCrosstabulations and Scatter Diagrams

Learning Goals1.Learn how to construct and interpret summarization procedures for qualitative data such as : frequency and relative frequency distributions, bar graphs and pie charts.2.Learn how to construct and interpret tabular summarization procedures for quantitative data such as:3.frequency and relative frequency distributions, cumulative frequency and cumulative relative frequency distributions.4.Learn how to construct a dot plot, a histogram, and an ogive as graphical summaries of quantitative data.5.Be able to use and interpret the exploratory data analysis technique of a stem-and-leaf display.6.Learn how to construct and interpret cross tabulations and scatter diagrams of bivariate data.

Summarizing Qualitative DataBrown Smith Davis Johnson Williams Williams Johnson Jones Davis Williams Jones Smith Smith Davis Johnson Smith Jones Jones Williams Smith Brown Smith Johnson Jones Smith Smith Williams Williams Johnson Williams Johnson Williams Smith Brown Smith Davis Brown Smith Johnson Brown Johnson Brown Jones Davis Smith The six most common last names in the U.S. are Brown, Davis, Johnson, Jones, Smith, and Williams. A sample of 50 individuals with one of these last names is shown in the above table .At issue:How do we summarize the information in the above box?Jones Johnson Brown Johnson Davis

To summarize this information we will make use of:•Frequency distributions•Relative Frequency•Percent Frequency Distribution•Bar Graph•Pie Chart

Summarizing Qualitative Data•A frequency distribution: a tabular summary of data showing the frequency (or number) of items in each of several nonoverlapping classes.•The objective is to provide insightsabout the data that cannot be quickly obtained by looking only at the original data.

Summarizing Qualitative Data:Summarizing last names using a frequency DistributionLast NameFrequencyBrown7Davis6Johnson10Jones7Smith12Williams8Total50

Qualitative Data:Relative Frequency Distribution•The relative frequencyof a class is the fraction or proportion of the total number of data items belonging to the class.•A relative frequency distributionis a tabular summary of a set of data showing the relative frequency for each class.

•The percent frequencyof a class is the relative frequency multiplied by 100.