Which type of scale is being used if a respondent's age is ...

[washai]

Which type of scale is being used if a respondent's age is measured by the question How many years have elapsed since your 18th birthday?
 a. nominal scale c. interval scale
  b. ordinal scale d. ratio scale

Question 2

If Delta Airlines selects randomly a set of 40 flights on a given day, and then selects randomly a group of ten passengers on each of these flights to participate in an in-flight survey, the passengers are _____.
 a. PSU
  b. census
  c. systematic samples
  d. secondary sampling units

[Zebsrer]

Answer to Question 1

C
It is an interval scale, because the property of equal differences applies, but the property of equal ratios does not (someone 10 years past their 18th birthday is not twice as old as someone 5 years past their 18th birthday).

Answer to Question 2

D

[washai]

Thanks for the timely response, appreciate it

[peter]

Gracias!