Question

Let's say you take a 10 question multiple choice test. Each question has 4 choices and you guess on all of them. What is the probability you get 7 or more right?

Answer 1

Answer:25%

Explanation:

Answer 2

In a multiple choice question the probability of success is : p = 1/4 = 0.25

and the probability of failure is : q = 3/4 =) 0.75

r = 7 ( correct answers )

Probability = 10 C r * ( 1/4 ) ^(10- r) * ˙( 3/4 )^r =

= 10 C 7 * ( 0.25 )^3 * ( 0.75 )^7 =

= 120* 0,00208568572 =

= 0,2502822864

Answer: Probability is 0,2502822864 or 25.02822864 %.