Answer:
(a) 0.0178 <= p <= 0.0622
(b) p <= 0.0586
Step-by-step explanation:
We have that the sample proportion is:
p = 12/300 = 0.04
(to)
For 95% confidence interval alpha = 0.05, so critical value of z will be 1.96
Therefore, we have that the interval would be:
p + - z * (p * (1-p) / n) ^ (1/2)
replacing we have:
0.04 + - 1.96 * (0.04 * (1-0.04) / 300) ^ (1/2)
0.04 + - 0.022
Therefore the interval would be:
0.04 - 0.022 <= p <= 0.04 + 0.022
0.0178 <= p <= 0.0622
(b)
For upper bounf z-critical value for 95% confidence interval is 1.645, so upper bound is:
p + z * (p * (1-p) / n) ^ (1/2)
replacing:
0.04 + 1.645 * (0.04 * (1-0.04) / 300) ^ (1/2)
0.04 + 0.0186 = 0.0586
p <= 0.0586
