Question 1065512: Assume that you are taking a
seven
-question
true or false quiz.
a.
How many different ways are there to answer all seven
questions?
b.
How many ways are there to get no questions wrong? One question? Two questions?
c.
If, not having studied, you simply guess at each answer, what are your chances of getting five
or more correct?
Answer by math_helper(2461)   (Show Source):
You can put this solution on YOUR website! a) Since each answer can be true or false, there are 2 ways to answer each question.
There are 2x2 = 4 ways [(T,T), (T,F), (F,T), (F,F) ] to answer two questions.
Extending this reasoning to all seven questions, there are
 ways to answer all seven questions.
b) To get no questions wrong: there is only  way for that to happen.
To get one question wrong: there are  ways for that to happen.
To get two questions wrong: there are  ways for that to happen.
c) This part makes use of (a) and (b), can you solve?
I will give you a couple hints:
Hint1: Pr{5 or more correct} = Pr { 2 or fewer incorrect}
Hint2: Think number of ways X can happen, divided by total number of ways to answer all seven.
Hint3: 0.2265625
|
|
|
