Posted by Lina on .
Please, give the formula and steps to do this problem. Thank you
The average length of a flight by regional airlines in the United States has been reported as 299 miles. If a simple random sample of 30 flights by regional airlines If The average length of a flight by regional airlines in the United States has been reported as 299 miles. If a simple random sample of 30 flights by regional airlines were to have ȭ = 413/6 miles and s= 42.8 miles, would this tend to cast doubt on the reported average of 299 miles? Use a twotail test and the 0.05 level of significance in arriving at your answer

statistics 
PsyDAG,
Is the random sample mean 41.5 (41 3/6) miles or 68.833 (413 divided by 6)? Either way, you do not have to do any calculation, since either value is over 5 standard deviations away from 299 miles.
However, to do a calculation, follow these steps.
Z = (mean1  mean2)/ Standard Error (SE) of difference between means
SE of difference = Sq root of (SE1^2 + SE2^2)
SE = Standard Deviation/ Sq root of n1
When only one measure of variability is available, it is used as the best estimate of SE of difference.
I hope this helps. Thanks for asking. 
statistics 
Nancy Castillo,
WHAT IS WRONG WITH THESE STATEMENT?
The United Nations Organization declared that the world’s sixbillionth inhabitant was born on October 12, 1999 in Bosnia.