to eliminate outliers in the graph

[Roman Alpatov 2]

Hello,

I wanted to eliminated outliers from the graph. Does anybody know how to dot this in Spotfire Analyst.

Thank you.

[Fabian Duerr]

I think there are a couple of ways to do this... Here are two suggestions:

You could add a calculated column that evaluates TRUE/FALSE when a value is/is not an outlier and then filter on this column.

Or you can directly limit the data in your visualization by going to the properties -> data ->limit by expression and using somethings like (replace [Y] with your column on the Y axis):

[Y] < Avg([Y]) + 3*StdDev([Y]) AND [Y] > Avg([Y]) - 3*StdDev([Y])

This formula would check whether your data point is within 3 times the standard deviation. But of course, you can change the definition of your outliers. Just make sure that you have a booleanexpression.

You can combine both approaches also with a document property (that for example takes the place of factor 3 in the above calculation) to adjust your outlier calculation quickly.

[Alain Martens]

Another thing you could do is create a scatterplot for your data. Then mark the outliers (for example by holding your ALT button down and drawing a lasso arround the outliers). Then right click and select 'Marked Rows' adn select 'Filter Out'. This will create a new column called 'Filtered out at ' column which holds 2 values yes/no. Automatically a filter is applied to not shows these values. You can choose to include the values by removing the filter from this column.

Best regards,

Alain Martens