in this forum you should only ask questions on the material that I cover in my lectures. :)

however, this problem is an obvious bimodal population distribution. 

let's say the population has only 1s and 2s

you take a sample of size 2, it can be one of the following three cases:

1, 1

2, 2

1, 2

the means will be 1, 2, 1.5 respectively

so the sampling distribution will have three clusters