On the below question, how did they decided the two probabilities of guessing the correct and wrong answer on a question? Where did the 0.25 and 0.75 come from?
The probability of achieving exactly k successes in n trials is shown below.
Formula:
n = number of trials
k = number of successes
n - k = number of failures
p = probability of success in one trial
q = 1 - p = probability of failure in one trial
Example: You are taking a 10 question multiple choice test. If each question has four choices and you guess on each question, what is the probability of getting exactly 7 questions correct?
n = 10
k = 7
n - k = 3
p = 0.25 = probability of guessing the correct answer on a question
q = 0.75 = probability of guessing the wrong answer on a question