Answer:
0.95345
Explanation:
Given that :
Number of files (n) = 200
Probability of getting damaged (p) = 0.2
q = 1 - p = 1 - 0.2 = 0.8
using normal approximation:
Mean (m) = np = 200 * 0.2 = 40
Standard deviation (s) = √n*p*q= √(200 * 0.2 * 0.8) = 5.6568542
P(X < 50)
X = 50 - 0.5 = 49.5
Find the standardized score :
Z = (x - m) / s
Z = (49.5 - 40) / 5.6568542
Z = 9.5 / 5.6568542
Zscore = 1.6793786
P(Z < 1.6793) = 0.95345 ( using Z probability calculator)
