<span>Third variables are common problems that add or introduce additional explanations for a reaction or occurrence. That means that when conducting test, the variable is not the only consideration of cause, and the effect of the third variable must be analyzed and isolated from the overall results, otherwise the data is influenced and inaccurate.</span>
Answer:
Callous
Explanation:
Showing the counters of tuition $200 per credit.
Answer: correct evaluation and medium of exchange etc.
Explanation: The main problem with the barter system is that it would be hard to value the goods or services that the parties are exchanging. In the given case, it would be hard to value how many car washes would be equal to a paint of house.
Also finding someone who is willing to paint house in exchange of car washes is another difficult task.
