hello,

In 3rd semester of BCA they have elements of statistics. In computer world linear algebra and statistics and probability plays a very vital role. This is because we keep on comparing present with past and predict future and try to optimize. For this we need to be clear with our basic concepts and even have to be strong in it. For this reason they have kept it. It is there in all the streams of computer science  or any related once too. So no need to worry. You can get tutorials from youtube and NPTEL for basics concept. You can learn from there. You can even ask your teacher.

Hope it helps!