June 21, 2012

Objectives  Enable the Data Analysis Add-In  Quickly calculate descriptive statistics using the Data Analysis Add-In  Create a histogram using the Data Analysis Add-In

Data Analysis Add-In  Microsoft Excel comes with several tools that can expand its ability to perform certain types of analysis  One of these tools is the Data Analysis Add-In  Other great add-ins, such as the: Solver add-in and Conditional Sum wizard

What is the Data Analysis Add-In  It provides easy to use tools to quickly generate a variety of statistics for a set of data Descriptive Statistics Histograms and Pareto Charts Regressions Analysis of Variance (ANOVA)

Begin Using Add-Ins  Add-ins are called such because they are not normally active in a default installation of Excel  The User controls which add-ins are available at start-up  Can also turn add-ins off and on as needed.  BUTTON[Excel Options] {Add-Ins}

Begin Using Add-Ins  Click on the Office Button  Click Excel Options  Click Add-Ins in the list on the left side of the window. The Add-In list shows which add-ins are activated, and which ones are available  At the bottom of the window, make sure the Manage drop down displays Excel Add-Ins

Begin Using Add-Ins  Click the Go button  The Add-Ins window appears.  Click the check box for: Analysis ToolPak  Click the OK button  OPEN A WORKBOOK  Go to the Data tab – Analysis group and click on the Data Analysis button

Data Analysis Options

Descriptive Statistics  Using the Descriptive Statistics tool can quickly generate a set of values that can help describe the data set  Summarizes the data set using a variety of statistical functions

Descriptive Statistics  Some of the values returned by the Descriptive Statistics tool: Range Min Max Range Sum Count Mean (Average) Median (middle value from a list of data) Mode (Most Often – value) Sample Variance Sample Standard Deviation

Descriptive Statistics  Open a Workbook to process  Open the Data Analysis window  Select the Descriptive Statistics option in the list  Click the OK button  The Descriptive Statistics dialog box opens

Descriptive Statistics  Select the Input Range (the data you want descriptive statistics generated for)  Select whether the data is grouped in columns or rows  Select if there are labels in the first row or column

Descriptive Statistics  Select the Output Range (where you want the data to be placed) USUALLY in the NEW WORKSHEET PLY  Click the Summary statistics check box  Click the OK button

Descriptive Statistics Data Analysis Pledges

Histograms  A Histogram is a type of chart used to display information about a data set Essentially, a bar graph applied to numerical data  Shows how many data points fall within various ranges of values  Also shows the “shape” of the data – how it is distributed

Creating Histograms  Determine the range of values to use – also called a bin range Excel can create bin ranges for you, but they are often meaningless bin ranges  Take the range of values of the data, and divide into 8 to 15 equally spaced categories  Create a bin range list in your worksheet

Creating Histograms  Click the Data Analysis button to start the Data Analysis Add-In (Data tab – Analysis group)  Select Histogram from the Analysis Tools list, and click OK  The Histogram dialog box opens

Creating Histograms  Select your input range, which is the range of data you are creating the histogram for It is a good idea to include a label with the data, so the x-axis of the chart is labeled with something meaningful  Select the bin range you created. This is a 2 column frequency table. BinFrequency More0

Creating Histograms  Click the Labels check box, if your data and bin range includes labels (again, a good idea)  Select where you want the histogram to be displayed (Usually NEW WORKSHEET PLY)  Make sure you Click the Chart output check box, otherwise the actual histogram chart will not be generated  Click the OK button

Creating Histograms

Histogram Formatting  Histograms usually do not have gaps between the bars, in order to better show the “shape” (distribution) of the data Select the data markers (single-click one of the bars) Go to the Chart Tools Layout tab – Current Selection group Click on the Format Selection button Change the Gap Width to zero

Histogram Shape  The size of the bars generally indicates variability of the data  Higher bars means less variability More data fits into fewer bins  Lower bars means more variability More data is distributed across the bin range

Histogram Shapes  The shape of most histograms will fall into one of four categories: Symmetric Positively Skewed (skewed right) Negatively Skewed (skewed left) Multiple Peaks

Histogram Shapes  Symmetric Has a single peak in the middle The bars on either side of the peak bar are roughly the same size Looks like a standard bell curve

Histogram Shapes  Positively Skewed (skewed right) Has a single peak The values of the data set extend much further to the right of the peak than the left The chart tails off to the right (data is grouped mostly to the left side of the chart)

Histogram Shapes  Negatively Skewed (skewed left) Has a single peak The values of the data set extend much further to the left of the peak than the right The chart tails off to the left (data is grouped mostly to the right side of the chart)

Histogram Shapes  Multiple Peaks Has more than one peak in the chart Generally indicates that data from two or more sources is being graphed together Chart has a U-shape

Exercise  Use the Data Analysis Add-In to: Generate a set of descriptive statistics Create a histogram chart Advanced ExerciseData Analysis Pledges Analysis