You hypothesise that the RNA is transcribed by RNA polymerase III, and positively or negatively effects the rate of rRNA maturation by regulating the rate of excision by one or more of the RNases involved in rRNA maturation.

Let's break this down.

You hypothesise that:

1) The RNA is transcribed by RNA polymerase III

2) The presence of the small RNA affects the rate of excision by [one or more of] the RNases

3) The rRNA maturation rate changes because of this

If I was approaching this question in the lab, I'd probably try to solve 1) and 2) at the same time, while leaving 3) until I saw the results from 2). I don't know what format your professor wants your report in, but I would usually write a research plan for myself in the form of: if x, then y, otherwise z.

So:

What experiment/s would you do to test whether a small RNA is transcribed by RNA polymerase III? Think about what you could use as positive and negative controls, and about how much biological replication you might need to do.

How many RNases are involved in rRNA maturation? Can you think of a way to narrow down which ones your small RNA might interfere with? (Hint: if it has partial complementarity to the rRNA, perhaps it anneals near or over the RNase recognition site. Where in the pre-rRNA sequence does the small RNA anneal? Do any of the RNases cut near that position?) Once you have thought about a mechanism by which it might interfere, can you think about any experiments that you could do to test this?

Remember that the aim of your experiments should be to determine WHETHER your hypothesis is true or false, NOT to prove that it is true. The best designed experiments will give you useful information about the hypothesis one way or the other.