Wayfair sent five different versions of their email to customers to determine which message was most effective at getting customers to make online purchases. while online sales rose by nearly 20%, two of the versions demonstrated higher than normal click-through rates. such experimentation done in a realistic environment would be called a

Field experiments

Explanation:

Field experiments is referred to as or known as randomly assigning the subjects to either control groups or treatment, done in order to access the claims of the causal relationships. The random assignment tends to help in order to establish comparability of control group and treatment, such that any differences in between them that tend to emerge after treatment are administered and governed plausibly tends to reflect influence of these treatment instead of the pre-existing differences in between these groups.

b. take periodic breaks and alternate between tasks.  

will increase work efficiency, and avoid health issues.

if you use only 25 for your entertainment and only 200 for the groceries that you really need and take out the 50 per month for the computer then that should be enough