SOLUTION: Passenger comfort is influenced by the amount of pressurization in an airline cabin. Higher pressurization allows a closer-to-normal environment and a more relaxed flight. A study

Question 1068633: Passenger comfort is influenced by the amount of pressurization in an airline cabin. Higher pressurization allows a closer-to-normal environment and a more relaxed flight. A study by an airline user group recorded the corresponding air pressure on 30 randomly chosen flights. The study revealed a mean equivalent pressure of 8000 feet with a standard deviation of 300 feet.
Develop a 99% confidence interval for the population mean equivalent pressure.
How large a sample is needed to find the population mean within 25 feet at 95% confidence?

Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
CI is 8000+/-t df=29,0.995 *300/sqrt(30); t value is 2.756
interval width is 2.756*300/sqrt(30)=150.95
(7849,8151)
----------------
interval is 25=z*300/sqrt(n)
I use z, because the sample size is large, and I can always then use t for that df and see if it changes the result.
25=1.96*300/sqrt(n)
25 sqrt(n)=1.96*300=588
sqrt(n)=588/25=23.52
square both sides
n=553.19 round to 554. With this size sample, t=z.
When I use this in the calculator for a t-test, I get an interval of +/-25.
RELATED QUESTIONS
the average weight of a suitcase for an airline passenger is 50 pounds. the standard... (answered by Theo)

the average weight of an airline passenger suitcase is 45 pounds. The standard deviation... (answered by stanbon)

The average weight of the passengers of an airline has increased from 150 pounds in 2000... (answered by ewatrrr)

A cruise ship is being designed. It can have two types of rooms for passengers-suites and (answered by Theo)

. An airline company has two types of airplanes: one for 10 passengers and one for 20... (answered by stanbon)

If a cabin has an area of 528 square feet and its length is 18' what is the width of the... (answered by nerdybill)

Airline passengers arrive randomly and independently at the passenger-screening facility... (answered by GingerAle)

To determine customer opinion of their check-in service, a major airline randomly selects (answered by Boreal)

Hi , I need a help ! Please solve it....tutor An investigator follows the stock... (answered by Fombitz)