Identify the type of sampling method used in each situation: At a large university, all instructors in 3 office buildings are interviewed to...

1. Identify the type of sampling method used in each situation:  

a. At a large university, all instructors in 3 office buildings are interviewed to determine their level of research interest.

b. A manufacturer checks every 20th product on its assembly line for quality assurance.

c. 6 lottery balls are drawn from a hopper of 269 equal size balls.

d. Everyone who walks into the grocery store between 3:00pm and 5:00 are asked their opinion about a new traffic light being installed next door.