Surely you can't process floating point values with "Integer.parseInt" - replace it with "Double.parseDouble", a takzhe nujno zamenit vse peremennie tipa "int" na peremennie tipa "double".
I stoit obratit vnimanie chto texty na lubih yazikah otlichnih ot anglijskogo zatrudnitelny dlia chtenia.
By the way it looks you have stolen your code from here:
How to Write a Program in Java to Calculate the Mean - wikiHow
I recommend you to write your codes completely yourself if you want to learn anything at all.