Answer:
0.25
Step-by-step explanation:
Given that:
Number of options per question = 4
Number of correct answer per question = 1
Number of incorrect answers per question = 3
By random guess:
Probability of picking a correct answer :
Number of correct answers / number of options
= 1 / 4 = 0.25
Probability of picking an incorrect answer :
Number of incorrect answers / number of options
= 3/4
Hence,
X :______ 4 _____ - 1
P(X) : ___ 0.25 __ 0.75
Σ(X*P(x))
(4 * 0.25) + (-1 * 0.75)
1 + (-0.75)
1 - 0.75
= 0.25
