A student randomly guessed the answers to a five question true/false test (there is a 50% chance of guessing correctly on each question). Find.

Question

1. the probability that the student answers more than 1 question correctly
2. the expected number of correct answers
3.the standard deviation
PLEASE HELP!!!

Answer 1

This is a binomial distribution. A tree diagram or 2^n will give you the sample space of 32. Then:

1. P(X>1) = 1 - P(X=0) - P(X=1)
= 1 - 1/32 - 5/32
= ?

2. Mean = np
= (5)(0.5)
= ?

3. SD = sqrt(np(1-p)
= ?