We show the first two steps of the Data Import Wizard only for reference, as their options have already been discussed in previous chapters.
Our test dataset consisting of 10,000 records was saved as a CSV file, so we start the import process via Main Menu > Data > Open Data Source > Text File
.
Note the missing values in columns X1_obs
, X2_obs
, and X4_obs
in the Data Panel. Column X5_obs
features Filtered Values, which are marked with an asterisk (*).
The next step of the Data Import Wizard requires no further input, but we can review the statistics provided in the Information Panel: we have 5,547 missing values (=11.09% of all cells in the Data panel) and 1,364 Filtered Values (=2.73%).
The next screen brings us to the core task of selecting the Missing Values Processing method. In the screenshot, the default option Structural EM is pre-selected, but we will explore all options systematically from the top. The default method can be specified under Main Menu > Window > Preferences > Data > Import & Associate > Missing & Filtered Values
.
We explain and evaluate each Missing Values Processing method separately. Please select the topic below or open it in the navigation bar.