A group of investigators measure student reaction time using special googles to simulate effects of alcohol on vision. For random sample of 9 college students, the time it takes to bring the vehicle to a stop from a speed of 60 miles per hour was recorded first with the googles and then without the googles. They want to assess if stopping time wearing the goggles is larger than the stopping time when not wearing the goggles? If the X_diff is X_goggles - X_{no_goggles}; the alternative hypothesis would be:

Select one:

a.

HA: X_goggles - X_{no_goggles}> 0

b.

HA: X_goggles - X_{no_goggles}= 0

c.

HA: X_goggles - X_{no_goggles}< 0

d.

HA: X_goggles - X_{no_goggles} 0