SOLUTION: Testing the variance Suppose an airline claims that its flights are consistently on time with an average delay of at most 15 minutes. It claims that the average delay is so co

Question 1058050: Testing the variance
Suppose an airline claims that its flights are consistently
on time with an average delay of at most 15 minutes. It claims that the average delay is so consistent that the variance is no
more than 150 minutes. Doubting the consistency part of the claim, a disgruntled traveler calculates the delays for his next
25 flights. The average delay for those 25 flights is 22 minutes with a standard deviation of 15 minutes.

My questions below
what is the df=_______ ?
Let a= 0.05
Decision ________
Conclusion write out in complete sentence
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
Our Ho is variance = 150 minutes and H1 is variance > 150 minutes
:
******************************************************
degrees of freedom(df) = sample size - 1 = 25 - 1 = 24
******************************************************
:
Note that variance = (standard deviation)^2
:
variance of the sample = 15^2 = 225
:
H1 does not contain an =, therefore we use a one-tailed test
:
Our test statistic is calculated
:
c = ((25 - 1) * 225) / 150 = 36
:
alpha(a) = 0.05
:
we check the chi-square distribution table
:
df of 24 and a = 0.05 gives us a probability value(p-value) of 0.0549
:
******************************************************************************
since our p-value > 0.05, there is no reason to reject our null hypothesis(Ho)
******************************************************************************
:
RELATED QUESTIONS
The managers of an airline analyzed a random sample of flights and found that 95% of the... (answered by rfer)

An airline claims that the no-show rate for passengers booked on its flights is less than (answered by Theo)

Please help me solve problem. Three airlines serve International airport. Airline A... (answered by stanbon)

Please help me solve problem. Three airlines serve International airport. Airline A... (answered by Boreal)

The probability that a flight is on time at a large airline is 95%. If the probability... (answered by Boreal)

The rates of on-time flights for commercial jets are continuously tracked by the U.S.... (answered by stanbon)

The rates of on-time flights for commercial jets are continuously tracked by the U.S.... (answered by jim_thompson5910)

Find the P-value for the indicated hypothesis test. An airline claims that the no-show (answered by Boreal)