Answer:
0.48173
Step-by-step explanation:
Given that :
Mean (m) = 2.24
Standard deviation (s) = 1.38
Sample size (n) = 40
P(x ≥ 2.55)
Z = (x - m) / (s/sqrt(n))
Z = (2.55 - 2.24) / (1.38 / sqrt(40))
Z = 0.01 / 0.2181971
Z = 0.0458301
P(Z ≥ 0.0458) = 0.48173 ( Z probability calculator)