How much would each hauling company charge to haul 40 cubic yards of dirt?
1 answer:
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Answer : 0.0129
Step-by-step explanation:
Given : Based on FAA estimates the average age of the fleets of the 10 largest U.S. commercial passenger carriers is years and standard deviation is
years.
Sample size :
Let X be the random variable that represents the age of fleets.
We assume that the ages of the fleets of the 10 largest U.S. commercial passenger carriers are normally distributed.
For z-score,
For x=14
By using the standard normal distribution table , the probability that the average age of these 40 airplanes is at least 14 years old will be :-
Hence, the required probability = 0.0129
Answer:
0.0417
Step-by-step explanation:
Given the following;
p = 0.7, n=121
The sampling distribution of sample proportion will be approximately normal with mean
\mu_{\hat{p}}=p=0.7
and standard deviation
\sigma_{\hat{p}}=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.7\cdot 0.2}{121}}=0.0417
Check attachment for the curve diagram.
