make up a set of at least twelve numbers that have the following landmarks. maximum: 8, range: 6, mode: 6, median:5

"maximum: 8, range: 6" gives you your minimum number, so pencil that in, and 8 at the other end of course to make your maximum.

Now, if you know what mode and median mean, you should be ready to write in some 6s, and spread about the same number of lower digits.