What is the question is the o
A + B + C = 518 ft^3
A = 1/3B, or 3A = B
B = C
A + B + C = 518 ft^3
1/3B + B + B = 518
7/3B = 518
B = 518×3/7 = 222 ft^3
A = 1/3B = 1/3×222 = 74 ft^3
C = B = 222 ft^3
We need to see the exercise before that or we cant solve it!
Answer:
90% CI expects to capture u 90% of time
(a) This means 0.9 * 1000 = 900 intervals will capture u
(b) Here we treat CI as binomial random variable, having probability 0.9 for success
n = 1000
p = 0.9
For this case, applying normal approximation to binomial, we get:
mean = n*p= 900
variance = n*p*(1-p) = 90
std dev = 9.4868
We want to Find : P(890 <= X <= 910) = P( 889.5 < X < 910.5) (integer continuity correction)
We convert to standard normal form, Z ~ N(0,1) by z1 = (x1 - u )/s
so z1 = (889.5 - 900 )/9.4868 = -1.11
so z2 = (910.5 - 900 )/9.4868 = 1.11
P( 889.5 < X < 910.5) = P(z1 < Z < z2) = P( Z < 1.11) - P(Z < -1.11)
= 0.8665 - 0.1335
= 0.733
