Question: 2018 Fall Midterm - 17
This midterm has 17 questions. For each question, four options are given. Assume that you answer each
question, by choosing one of the four options uniformly at random.
Define the event
Define the event
- A = "you answer exactly 7 questions correctly".
(a)
$\frac{{17 \choose 7}}{4^{17}}$
(b)
$\frac{4^{17}}{{17 \choose 7}}$
(c)
$\frac{{17 \choose 7} \cdot 3^{10}}{4^{17}}$
(d)
$\frac{{17 \choose 7} \cdot 2^{10}}{4^{17}}$