please help with hw

Do people walk faster in the airport when they are departing or when they are arriving? Researchers measured the walking speed of 52 departing travelers and 74 arriving travelers at Sacramento International Airport. They found that departing travelers had a mean walking speed of 252 ft/min, and arriving travelers had a mean walking speed of 239 ft/min. The standard deviation was 38 ft/min for departing travelers and 50 ft/min for arriving travelers. a. Construct a 85% confidence interval for the difference in mean walking speed between departing and arriving travelers. Critical value: 2* or t* = C] (Enter the positive one.) b. Interpret your result in part (a) in a complete sentence. c. Based on your condence interval, can you conclude that departing travelers walk at a different speed than arriving travlers? OYes O No