Which of the following should a researcher be concerned about when conducting a sample survey?

a. Having an accurate and complete list of the population under study.
b. Being unable to contact some of the units selected into the random sample. c. Bias that arises because of the failure of respondents to answer questions honestly.
d. Questions phrased in such a way as to lead the respondent to reply in a specific way.
e. All of these answers are correct.

All the answers are correct because research is multifaceted

Explanation:

While doing population studies, it is important to understand the population and they demographic, age, sex, location etc. This could have incredible effects on comparative studies.

It is also important to maintain an open line of communication to give instructions and follow up on the persons in the event that this kind of data is required. But like with population study the error that often comes into play is the element of human dishonesty. By keeping an open line of communication, the provisions can be made to keep this under check.

Finally, making sure that all the participants understand what is being asked of them is key to the open line of communication as not to create any misgivings or misunderstanding.

in 342 bc j._c. egypt fell into the hands of the persians, under the reign of nectanebo ii

greek city-states unite in a revolt against the persian empire at the beginning of the fifth century bc. j.-c  

from the year 660 or 659 bc ad, cyrus preached the revolt against the medes to deliver the persians.