Asked by Nora

Suppose a multiple choice test has 20 questions with each question having 4 choices, only one of which is correct that is %25. suppose an unprepared student writes the answers, each time randomly picking on the 4 choices. what is the probability that the student will get
A) exactly 4 answers correct
B)All the answers incorrect
C) at least 8 correct
D) what is mean and the standard deviation