Question

one more question on the same subject.


A student guesses the answers to 6 questions on a true-false quiz. Find the probability that the indicated number of guesses are correct:

no more than 2 (Hint: No more than 2 means exactly 0 or exactly 1 or exactly 2.)

Answer 1

then your job is to compute exactly 0 right, exactly 1 right, and subtract those from one

Answer 2

of course it is math, that is why she is guessing

Answer 3

i see now

Answer 4

exactly none means all wrong
only one way to get all wrong, namely
wrong wrong wrong wrong wrong wrong

probability is therefore
\[\frac{1}{2^6}\] for all wrong

Answer 5

would it be 2/2^6 for 1 right?

Answer 6

one wrong there are 6 possibilities

Answer 7

or one right, same thing

Answer 8

R W W W W W
W R W W W W
W W R W W W
W W W R W W
W W W W R W
W W W W W R

Answer 9

i think i got my answer, total is gonna be .08-.09

Answer 10

otherwise known as \(\dbinom{6}{1}=6\)

Answer 11

so it is
\[1-\frac{1}{2^6}-\frac{6}{2^6}=1-\frac{7}{2^6}\]

Answer 12

Excellent, thanks :)