The Sample operation generates a subset of your data. Use the Sample operation when you have a large amount of data and you want to work on a representative sample for faster prototyping. The Sample operation is in the ORGANIZE category. Choose one of two methods to create a sample. With a random sample, each row has an equal probability to be included in the sample data. You can choose a random sample by number of rows or by percentage of data. A stratified sample builds on a random sample. As with a random sample, you specify the amount of data in the sample (rows or percentage). With a stratified sample, you divide the data into one or more subgroups called strata. Then you generate one random sample that contains customized data from each subgroup. For Method, if you choose Auto, you select one column for the strata. If you choose Manual, you specify one or more strata and for each strata you specify filter conditions that define the rows in each strata. In this airline data example, we'll create two strata. One strata defines 50% of the output to have New York City destination airports and the 2nd the strata defines the remaining 50% to have a specified flight distance.
In Specify details for this strata box, enter the percentage of the sample that will represent the conditions that you will specify in this 1st strata. The strata percentages must total 100%. Available operators for string data. 50% of the sample will have New York City area destination airports. Click Save. The 1st strata has one condition. In this strata, 50% of sample must meet the condition. Specify details: enter the percentage of the sample that will represent the conditions that you will specify in the 2nd strata. Available operators for numeric data. 50% of the sample will be for flights with a distance greater than 500. Click Save. The 2nd strata has one condition. In this strata, 50% of the sample must meet the condition. If you use multiple strata, the Sample operation internally...