For applying the filter you need to select the data on which you want to apply it so it will allow you to look at only data you select from the filter options.
There are four basic types of learning, they are: formal, informal, self directed and other directed learning.
Cache are the temporary files that are downloaded onto your computer while going on a website, to clear this, you are getting rid of any of the cache. Not what you downloaded yourself, what the internet page downloaded for you.