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

6 0

3 years ago

According to a certain news poll, 71% agreed that it should be the government's responsibility to provide a decent standard of l

finlep [7]

Answer:

0.3157

Step-by-step explanation:

Given that according to a certain news poll, 71% agreed that it should be the government's responsibility to provide a decent standard of living for the elderly,

Let A be the event that it should be the government's responsibility to provide a decent standard of living for the elderly, and B the event that it would be a good idea to invest part of their Social Security taxes on their own

P(B) = 41%=0.41

A and B are independent

Hence P(both)= $0.77(0.41) = 0.3157\\$

the probability that a person agreed with both propositions

= Probability for both A and B

= P(A) P(B) since A and B are independent

= 0.3157

3 0

3 years ago

A basketball was originally priced at $25, but Tucker waited to buy it until the basketball was on sale for 20% off. If he paid

kotegsom [21]

Answer:

The answer to your question is $21.0

Step-by-step explanation:

Data

Original price = $25

Discount = 20%

Taxes = 5%

Process

1.- Calculate the price with the discount

$25 ------------------- 100%

x ------------------- 20%

x = (20 x 25) / 100

x = 500 / 100

x = $5

Price after the discount = $25 - $5

= $20

2.- Calculate the price after taxes

$20 ---------------------- 100%

x ----------------------- 5%

x = (5 x 20) / 100

x = 100 / 100

x = $1

Final price = $20 + $1

= $21

3 0

3 years ago

A pair of angles which share a common side and vertex is called

zheka24 [161]

Answer: Adjacent Angles

3 0

3 years ago