Unit 7: Quantifying Uncertainty: Probability, Binomial, and Normal Distributions
In a mathematics competition, students try
to find the correct answer from five options
in a multiple choice exam of 25 questions.
Alex decides his best strategy is to guess all
the answers.
a. State an appropriate model for the
random variable A = the number of
questions Alex gets correct.
Find the probability that the number of
questions that Alex gets correct is:
b. at most five c at least seven
d no more than three,
e. Write down E(/4) and interpret this
value.
f. Find the probability that Alex scores
more than expected.
g. In the test, a correct answer is awarded
4 points. An incorrect answer incurs a
penalty of 1 point. If Alex guesses all
questions, find the expected value of his
total points for the examination,
h. Four students in total decide to guess all
their answers. Find the probability that
at least two of the four students will get
seven or more questions correct.
