Displaying variable depending on its probabilities?

i have these if queries in my backend at a update function:

if (currentVokabel.getCounter() <= 0) {
            currentVokabel.setProbability(1);
        } else if (currentVokabel.getCounter() == 1) {
            currentVokabel.setProbability(0.8);
        } else if (currentVokabel.getCounter() == 2) {
            currentVokabel.setProbability(0.6);
        } else if (currentVokabel.getCounter() == 3) {
            currentVokabel.setProbability(0.4);
        } else if (currentVokabel.getCounter() == 4) {
            currentVokabel.setProbability(0.2);
        } else if (currentVokabel.getCounter() == 5) {
            this.vokabelRepository.delete(currentVokabel);
        }

Now i want to work with these probabilities, such as displaying currentVokabel only 80% of all times, when i have a probability of 0.8 . Any ideas how?