Answer:
0.477%
6.55%
5.05%
Event in question (a)
Step-by-step explanation:
Given that:
p = 0.67 ; n = 80
Using Normal approximation :
Mean (m) = np = 80 * 0.67 = 53.6
Standard deviation (s) = sqrt(np(1-p)) = sqrt(80*0.67*0.33) = 4.2057
probability that the number who oppose raising the age is
(a) at least 65
65 - 0.5 = 64.5 = x
Z = (x - m) / s
Z = (64.5 - 53.6) / 4.2057 = 2.592
P(Z ≥ 2. 592) = 0.004771 (Z probability calculator)
(b) exactly 50
x = 50 + 0.5 = 50.5 ; x = 50 - 0.5 = 49.5
Z = (50.5 - 53.6) / 4.2057 = - 0.737
Z = (49.5 - 53.6) / 4.2057 = - 0.974
P(Z < - 0.737) - p(Z < 0.974) (Z probability calculator)
0.23056 - 0.16503 = 0.06553
(c) more than 60, and (d) identify any unusual events
x = 60 + 0.5 = 60.5
Z = (60.5 - 53.6) / 4.2057 = 1.64
P(Z > 1.64) = 0.0505
D.) Event with probability of less than 5%, which is event in (a) with probability of 0.477%
