Chapter 9: Summarization

Chapter 9: Summarization Transcript

The next several sections will deal with executing specific tasks which are commonly used in data analysis.

The first one we’ll look at is called Summarization. As the name implies, Summarization is about adding things up or getting a sum or total from your data.

The first thing I’m going to do, using the Sales Transactions database, is generate the transaction totals for each customer. To start, ensure the Sales Transactions database is open, and that data is selected in the properties window.

Next, select the Analysis tab and in the categorize group, click Summarization. This is the Summarization dialog box. The first thing I do is select which field I’m summarizing and which field I’m totaling. You can select up to 8 fields to summarize. In this example, I’m only looking at account totals for each customer number, but I could get a lot more granular by adding more in the “Fields to Summarize” list to let me see the totals for each customer number broken down by product code and maybe payment type if I wished.

For now, I’m going to keep it simple and just show totals for each customer, so I’m going to summarize by customer number. I only have one option for my total which is amount. The default action here is to provide a sum or a total of the field selected in the “Numeric Fields to Total” window but there are other statistics which I could choose to include.

I can also pick and choose which fields will be added to the output by clicking the Fields button. Currently, no additional fields are selected. This helps keeps the output clean and easy to read. Click the X or the OK button to return to the Summarization dialog box.

Next select the Use Quick Summarization checkbox on the left-hand side of the dialog near the bottom. This allows the task to run faster, but it does impose some limitations on the task’s functionality. For example, you will be restricted to data sets which have a maximum of 4000 unique keys to total, you are restricted to only using the Sum statistic, the others will be greyed out and you can only summarize on one field.

Finally provide a name for the new database you are creating. Call it Summarized Transactions and click OK.

So let’s have a look at the new database. You can see that it is summarized, or grouped by Customer number. There is a new field called Number of Records which shows how many transactions or records each customer had and a field called Amount_sum which is the total amount of each customer’s transactions.

Notice that the values in the Number of Records field are blue. These are clickable links which provide drill-down functionality to let you see all the records for each customer. This is the one record for the first customer.

And these are all the records for this customer. If I find someone who has particularly interesting information I can save the details as a new database, I can print them if I wish, or I can close the window by clicking Done.