In: Statistics and Probability
Expected average spending per member = 0.9 * 2000 + 0.1 * 50000 = 6800$
Assuming 0 administrative expenses as the question specifies, and that the estimate follows a normal distribution,
Mean of the normal distribution = 6800
Hence, the estimate , say X has the distribution, X ~ N(6800, 5002)
X <= 0 corresponds to Z-score of (X - mean)/StdDev = (0 - 6800)/500 = -13.6
Looking up the Z-score table, P(Z <= -13.6) 0
Hence, probability of insurance company losing money = P(X<=0) = 0