Answer:
0.8629
Step-by-step explanation:
Given :
Number of trials, n = 400
p = 0.25
q = 1 - p = 1 - 0.25 = 0.75
With the information given, we could use a binomial probability relation to solve :
Recall : P(x = x) = nCx * p^x * q^(n-x)
Therefore, the probability that between 75 (inclusive) and 95 (inclusive) can be interpreted as :
P(75≤X≤90) = P(X ≥ 75) - P(X ≤ 90)
Using a binomial probability calculator :
P(X ≥ 75) = 0.9987
P(X ≤ 90) = 0.1358
0.9987 - 0.1358 = 0.8629