Question

TravelAir.com samples domestic airline flights to explore the relationship between airfare and distance. The service would like to know if there is a correlation between airfare and flight distance. If there is a correlation, what percentage of the variation in airfare is accounted for by distance? How much does each additional mile add to the fare? The data follow. Distance Fare 636 $109 2,395 252 2,176 221 605 151 403 138 1,258 209 254 627 259 264 2,342 215 177 2,521 128 348 1,050 224 441 175 Origin Destination Detroit, MI Myrtle Beach, SC Baltimore, MD Sacramento, CA Las Vegas, NV Philadelphia, PA Sacramento, Seattle, WA CA Atlanta, GA Orlando, FL Boston, MA Miami, FL Chicago, IL Covington, KY Columbus, OH Minneapolis, MN Fort Lauderdale, Los Angeles, CA FL Chicago, IL Indianapolis, IN Philadelphia, San Francisco, PA CA Raleigh/Durham, Houston, TX NC Midland/Odessa, Houston, TX TX Dallas/Ft. Worth, Cleveland, OH TX Baltimore, MD Columbus, OH Boston, MA Covington, KY Kansas City, San Diego, CA MO Milwaukee, WI Phoenix, AZ Portland, OR Washington, DC Phoenix, AZ San Jose, CA Baltimore, MD St. Louis, MO Houston, TX Orlando, FL Houston, TX Seattle, WA Burbank, CA New York, NY Atlanta, GA San Diego, CA Minneapolis, New York, NY MN West Palm Beach, Atlanta, GA FL Kansas City, Seattle, WA ΜΟ Baltimore, MD Portland, ME New Orleans, was Washington, DC LA 256 121 252 206 167 308 1,021 336 752 1,333 1,460 2,350 621 737 853 1,894 2,465 1,891 1,028 152 175 191 231 251 291 260 545 123 1,489 452 969 211 139 243

Answer 1

Given that, sample size (n) = 30

b-2) The null and alternative hypotheses are

Hop<0

H1 :p> 0

Degrees of freedom = n - 2 = 30 - 2 = 28

Since, this is right-tailed test, t-critical value at significance level of 0.05 with 28 degrees of freedom is, t^* = 1.701

Decision Rule : Reject H0 if t > 1.701