Pollsters are very careful to avoid

Pollsters are very careful to avoid
 
  a. a random sample.
  b. a totally random sample.
  c. sampling bias.
  d. margins of error.
  e. independent voters.

Question -2-

In a random sample
 
  a. all age groups are taken into account.
  b. all ethnic groups are taken into account.
  c. every member of the population has an equal chance of appearing in the sample.
  d. all religious groups are taken into account.
  e. all political groups are taken into account.

Question -3-

A reputable national poll should have a sample size of at least
 
  a. 100 persons
  b. 10,000 persons.
  c. 14,000 persons.
  d. 500 persons.
  e. 1,500 persons.