18 (3.24) (a) give an example of a way to choose a sample of students that is poor practice because it depends on voluntary response. ask your friends to participate in the study. hang a sign that asks people to call a number to participate in a study about parking on campus. all the answers are correct.

All the answers are correct.

In order for a study to produce results that are significant for the population, the sample needs to be representative. One of the most important factors in making that sample representative is electing subjects in a random manner.

If the subjects are chosen from a group of friends or as volunteers, it is likely that sample will share common characteristics in higher numbers than the ones found in the population. Therefore, the final results could be biased.

the aksumite empire was an ancient kingdom located in what is now northern ethiopia from the period of 100 ad to 940 ad. its capital was the city of aksum. the kingdom established itself as one of the 4 great powers at its time, along with persia, rome, and china.

the kingdom was rich in goods like gold, iron, and salt. it established strong commercial ties with the regions governed by rome, egypt, and persia (arabia). aksum was a key location in this commercial network. trade was also facilitated with the introduction of the aksumite currency.