Could anyone help me out with the following problem?

Identify the consequences (i.e. increase, decrease, or none) that the following procedures are likely to have on both bias and sampling error in an experimental study.
A) Assigning treatments to subjects alphabetically, not randomly
B) Increasing sample size
C) Calculating power
D) Applying every treatment to every experimental unit in random order
E) Using a sample of convenience instead of a random sample
F) Testing only one treatment group, without a control group
G) Using a balanced design
H) Informing the human subjects which treatment they will receive

The main ones I'm struggling with are C,D, and E (especially C, because I would think it would depend on what the power was one you calculated it).

I pretty sure I have A,B, and F-H figured out, but I may be wrong. I'm thinking that A, F, and H will increase bias but have no effect on sampling error, whereas B and G will reduce sampling error but not affect bias.

1 answer

A) Increase bias, no effect on sampling error
B) Decrease sampling error, no effect on bias
C) Depends on the power calculated
D) No effect on bias or sampling error
E) Increase bias, decrease sampling error
F) Increase bias, no effect on sampling error
G) Decrease sampling error, no effect on bias
H) Increase bias, no effect on sampling error