Why will a researcher need more participants when there is a high degree of within-group variability?
a. the scores are spread out within the groups, which makes it more difficult to see differences between groups.
b. the scores are clustered together within the groups, which makes it more difficult to see differences between groups.
c. the scores are spread out within the groups, which makes it easier to see differences between groups.
d. none of the above?

The correct answer is a. the scores are spread out within the groups, which makes it more difficult to see differences between groups.

Explanation:

Within-group variability implies that each group has many different scores within itself. For example, Group 1 has both high and low scores, Group 2 also has high and low scores, and so on. This implies that the scores are spread out within groups, rather than clustered together within groups.

If the scores are spread out within groups, then it is more difficult to see differences between groups. This is because all the groups appear similar as there are hardly any distinguishing characteristics for each group. Therefore, the researcher needs more participants to define each group accurately. Hence, option a is the correct answer.

it would be d). more resources must be obtained to attain that combination of goods and services