An airline company would like to know if the average number of passengers on a flight in November is less than the average number of passengers on a flight in December. The results of random sampling are printed below:
November: n1=75 hours, x1_bar=476, s1=9
December: n2=80 x2_bar=482, s2=7
The null and alternative hypothesis used is: Ho: mu1-mu2=0 vs. Ha:mu1-mu2<0
Compute the test statistic for the null and alternative hypothesis? _________