Issue with Average for Card Visual

HI,

New to powerbi and still learning, thanks for having me.

I have a column in my excel files that works out networkdays.

However, there are some real outliers that I need to remove.

For example if there is no closed date the result of networkdays is -31322

So when I use a card visual to calcualte the average number of networkdays I am getting a very skewed result.

When I goto the Filters on that visual, I am not able to change anything. Is there a way I can filter so it only calculates results greater than zero.

Thanks,

Appreciate the help