What is it called when a researcher compares secondary data from ...

[jessicacav]

What is it called when a researcher compares secondary data from one source with data from another?
 a. data conversion
  b. cross-check
  c. data mining
  d. data enhancement

Question 2

If done correctly, stratified sampling can actually decrease the standard error of the estimator by
 a. making sure the strata are more homogeneous on the variables for which statistics will be calculated
  b. making sure each strata forms a representative sample of the population
  c. decreasing the number of categories within each of the variables for which statistics will be calculated
  d. making sure the sample is sufficiently large to ensure a lower sampling error

[bobsmith]

Answer to Question 1

B

Answer to Question 2

A
If the strata are more homogeneous than a simple random sample, the standard error of the estimator will be less.

[jessicacav]

Thanks for the timely response, appreciate it

[xiazhe]

Wow, this really help