Answer:
0.9642
Step-by-step explanation:
Sample proportion p follows a Normal distribution with mean = p0 = 0.23 and Standard deviation = √P0(1 - P0) / n = √0.23(1-0.23) / 869 = 0.0143
Then Z = p - mean / Standard deviation = X - 0.23 / 0.01343
P(0.2<p<0.26) = P(p<0.26) - P(p<0.2)
= P(p-023/0.0143 < 0.26-0.23/0.0143) - P(p-0.23/0.0143 < 0.2-0.23/0.0143)
= P(Z < 2.1) - P(Z < -2.1)
= 0.9821 - 0.0179
= 0.9642