a).

(a) All the senators of the United States presently in office:

This is a population because it involve all senators of United States.

(b) 1500 people selected to find out the soft drink preference in Chicago:

This is a sample because 1500 people is part of whole population in Chicago who prefer soft drink.

b).

(a) A survey to rank the famous television shows in the United States:

I will use sample. This is because viewers of the shows are very many, I will draw samples from various states and compute the most famous television shows.

(b) A research project to find how many heart attack patients are admitted on January 1 to a famous hospital:

I will use population. This is possible to use the whole population because time frame for the study is very small (one day).

(c) A study to find the quality of matchsticks in a bundle of 100 matchboxes:

I will use sample. This is because population of matchsticks is very large and impossible to count one by one.

(d) An evaluation of the creativity of the director of three films:

I will use population. Evaluation requires use of population because I need to know each director's strengths and weaknesses on my area of study. Therefore, it is impossible to use sample.