Randomly Limiting 50% of Data Points from Range 1–11 with Proportional Scaling

I want to take the data from 1 to 11 and randomly limit about 50% of them (meaning around 5 to 10 values).

The way the limiting should work is that each number in the range 0 to 1 gets proportionally scaled down to the range 0 to 0.5.

How can I apply this kind of limiting to the data from 1 to 11 shown in the image below?