Answer:
0.00004
Step-by-step explanation:
Given that:
n = 50
Number of options = 4 ; 1 is the correct answer
Hence ;
p = 1/4 = 0.25
Using normal approximation :
Mean (m) = np = 50 * 0. 25 = 12.5
Standard deviation (s) = √(n*p*q)
q = 1 - p = 1 - 0. 25 = 0.75
s = √(50*0.25*0.75) = 3.062
At least half the question :
Half the question = 1/2 * 50 = 25
P(X ≥ 25) = P(X ≥ 24.5)
(x - m) / s
P(X ≥ 24.5) = (24.5 - 12.5) / 3.062
= 12 / 3.062
= 3.919
P(Z ≥ 3.919) = 0.00004 (Z probability calculator)
