The statement of purpose is the main document required to get in to the University. There after experience in the filed of electrical engineering counts. Only 4 students will be give the research assistant job. If more than 4 are there, on performance basis the job will be given.

There are not many qualified or interested students. The professors select the best student who applies for the research assistant job. So, basically, it is up to you to prove your merits. If you have good grades and can show the interest in the research. It should do the work.