A pilot claims that average flight times from Charlotte to Miami are not more th
ID: 3388527 • Letter: A
Question
A pilot claims that average flight times from Charlotte to Miami are not more than 90 minutes. In a random sample of 35 such flights, the average time is 94 minutes with a standard deviation of 9 minutes. Assuming standard deviation of all such flights is 8 minutes, test the claim at the 1% level of significance.
State null and alternative hypotheses:
Determine distribution of test statistic and compute its value:
Construct the rejection region:
Make your decision:
State your conclusion:
Compute the p-value (observed level of significance) for this test:
Explanation / Answer
a)
Formulating the null and alternative hypotheses,
Ho: u <= 90
Ha: u > 90 [ANSWER]
********************
b)
Here, as n > 30, we use z distribution. [ANSWER]
As we can see, this is a right tailed test.
Getting the test statistic, as
X = sample mean = 94
uo = hypothesized mean = 90
n = sample size = 35
s = standard deviation = 9
Thus, z = (X - uo) * sqrt(n) / s = 2.629368792 [ANSWER, TEST STATISTIC]
*****************************
c)
Thus, getting the critical z, as alpha = 0.01 ,
alpha = 0.01
zcrit = + 2.326347874
Thus, Reject Ho if z > 2.326. [ANSWER]
*********************
d)
As z > 2.326, we Reject Ho. [ANSWER]
***********************
e)
Thus, there is significant evidence that the average flight times from Charlotte to Miami are more than 90 minutes. [CONCLUSION]
**********************
f)
Also, the p value is, as this is left tailed,
p = 0.004277177 [ANSWER]
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.