Question

Airliners taking off from City Central Airport produce a mean noise level of 108

dB (decibels), with a standard deviation of 6.7 dB. To encourage airlines to

refit their aircraft with quieter engines, any airliners with a noise level above

120 dB must pay a “nuisance fee”.

a.

What percent of the airliners will be billed a nuisance fee?

b.

After two years, a sample of 1000 airliners showed that 3 were billed

the nuisance fee. Assuming that the program has been effective, and

that the standard deviation has not changed, what is the new mean

noise level?

Answer #1

a)

for normal distribution z score =(X-μ)/σx | |

here mean= μ= | 108 |

std deviation =σ= | 6.700 |

percent of the airliners will be billed a nuisance fee:

probability
=P(X>120)=P(Z>(120-108)/6.7)=P(Z>1.79)=1-P(Z<1.79)=1-0.9633=0.0367
~ 3.67% |

b)

since top (3/1000)~ 3% will pay nuisance fee which is at 97th percentile:

for 97th percentile critical value of z= | 1.88 |

therefore new mean =X-z*standard deviation =120-1.88*6.7
=**107.404** dB

The ideal (daytime) noise-level for hospitals is 45
decibels with a standard deviation of 12 db; which is to say,
this may not be true. A simple random sample of 75
hospitals at a moment during the day gives a mean noise level of 47
db. Assume that the standard deviation of noise level for all
hospitals is really 12 db. All answers to two places after the
decimal.
(a) A 99% confidence interval for the actual mean noise level...

During a rock concert, the noise level (in decibels) in front
row seats has a mean of 96 dB with a standard deviation of 7 dB.
Without assuming a normal distribution, find the minimum percentage
of noise level readings within 9 standard deviations of the
mean.

The ideal (daytime) noise-level for hospitals is 45 decibels
with a standard deviation of 10 db. A simple random sample of 500
hospitals at a moment during the day gives a mean noise level of 46
db. Assume that the standard deviation of noise level is really 10
db.
Part One.
Assuming that the average noise level of hospitals is what it's
supposed to be, what is the probability of a sample of 500
hospitals producing an average as high...

The ideal (daytime) noise-level for hospitals is 45
decibels with a standard deviation of 11 db; which is to say,
this may not be true. A simple random sample of 80
hospitals at a moment during the day gives a mean noise level of 47
db. Assume that the standard deviation of noise level for all
hospitals is really 11 db. All answers to two places after the
decimal.
(a) A 99% confidence interval for the actual mean noise level...

The ideal (daytime) noise-level for hospitals is 45 decibels
with a standard deviation of 10 db; which is to say, this may not
be true. A simple random sample of 70 hospitals at a moment during
the day gives a mean noise level of 47 db. Assume that the standard
deviation of noise level for all hospitals is really 10 db. All
answers to two places after the decimal.(e) Assuming our sample of
hospitals is among the most typical half...

Delta airlines case study
Global strategy. Describe the current global
strategy and provide evidence about how the firms resources
incompetencies support the given pressures regarding costs and
local responsiveness. Describe entry modes have they usually used,
and whether they are appropriate for the given strategy. Any key
issues in their global strategy?
casestudy:
Atlanta, June 17, 2014. Sea of Delta employees and their
families swarmed between food trucks, amusement park booths, and
entertainment venues that were scattered throughout what would...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 10 minutes ago

asked 11 minutes ago

asked 16 minutes ago

asked 17 minutes ago

asked 20 minutes ago

asked 24 minutes ago

asked 24 minutes ago

asked 24 minutes ago

asked 27 minutes ago

asked 27 minutes ago

asked 27 minutes ago

asked 35 minutes ago