Why is research involving already existing groups rather than randomly assigned groups prone to the effects of extraneous variables?
What will be an ideal response?
When you use existing or intact groups, you don't have a guarantee that they are equivalent; that is, if you were to measure then on the DV, they might differ from the start. If you didn't know about this difference, you would mistakenly attribute a difference at the end of the study to the IV.
When groups are created by random assignment, there is less chance that the groups will differ systematically because differences that could be critical are spread out randomly across groups.
You might also like to view...
Following Khomeini's death, the Islamic Republican Party split into many different factions
Indicate whether this statement is true or false.
In December 2015, the Attorney General of Texas, under the leadership of Republican Governor Greg Abbott, sued the U.S. government to ______.
a. end NAFTA b. contest participation in the TPP c. receive proceeds from the NAFTA and TPP agreements d. block resettlement of Syrian refugees within the state