Suppose you would like to see if SkyWrite Ink has many repeat customers, and if so, who those customers are. You can perform a variety of calculations on your data using the provided options, and the seven aggregate calculations:
•Compute
•Tally
•Group
•Crosstab
•Aggregate
oCount
oMinimum
oMaximum
oSum
oAverage
oStandard Deviation
oVariance
•Duplicates
To get the information we want about our repeat business we will tally it. A tally counts the number of occurrences of each value in a column.
To count how many times a customer ordered flights:
| 1. | In the "Data Browser" window, choose Calculate: Tally: Select Column. |
The "Tally" dialog box displays the columns in the Flights table. We want to count the number of times each customer ID occurs in the table.
| 2. | Highlight "CustomerID", and click the OK button. |
The tally is displayed in the "Tally" window.
The values in the CustomerID column are sorted in ascending order and the number of occurrences for each value is displayed. You can see that customer number "1," who has booked four flights, does the highest volume of business. Close the "Tally" window when you are finished.
From time to time, SkyWrite Ink gives bonuses to its salespeople. You would like to know the number of sales each employee has made. Use the Tally option to display the number of sales for each employee.
