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Sati [7]
3 years ago
11

Based on FAA estimates the average age of the fleets of the 10 largest U.S. commercial passenger carriers is 13.4 years with a s

tandard deviation of 1.7 years. Suppose that 40 airplanes were randomly selected from the fleets of these 10 carriers and were inspected for cracks in these airplanes that are considered too large for flying. What is the probability that the average age of these 40 airplanes is at least 14 years old
Mathematics
1 answer:
Aliun [14]3 years ago
6 0

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 \mu=13.4 years and standard deviation is \sigma=1.7 years.

Sample size : n=40

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,

z=\dfrac{x-\mu}{\dfrac{\sigma}{\sqrt{n}}}

For x=14

z=\dfrac{14-13.4}{\dfrac{1.7}{\sqrt{40}}}\approx2.23

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 :-

P(x\geq 14)=P(z\geq2.23)\\\\=1-P(z

Hence, the required probability = 0.0129

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alukav5142 [94]

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The integers added up equal to 11.

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Fractions = 1/2, 3/4, 3/4 and 1/2.

We can add up 1/2 and 1/2 to equal 1, and 3/4 and 3/4 to make 1.5.

1 + 1.5 = 2.5          

Finally, we add up the answer for the integers and the fractions together, (11 + 2.5) which equals 13.5.

Our answer is 13.5 hours.      

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3 years ago
A quadtratic equation that has x intercepts of -8,0 and 2,0 and has a vertical stretch of 3
Paladinen [302]

Answer:

f(x) = 3(x + 8)(x - 2)

Step-by-step explanation:

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3 years ago
What is the most convenient method to solve the quadratic equation ( x + 4 )² = 15
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Answer:

Factoring

Step-by-step explanation:

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IgorC [24]

Answer:

30 gallons of 6% milk, and 45 gallons of 1% milk.

Step-by-step explanation:

x=quarts of 6% butterfat

<h2>First, write an equation.</h2>

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<h2>Multiply both sides by 100.</h2>

0.06x*100+0.01*100(75-x)=100*0.03*75

<h2>Simplify</h2>

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