To gather information about the validity of a new standardized test for tenth-grade students in a particular state, a random sample of 15 high schools was selected from the state. the new test was administered to every 10th-grade student in the selected high schools. what kind of sample is this? (a) a simple random sample (b) a stratified random sample (c) a cluster sample (d) a systematic random sample (e) a voluntary response sample

(c) A cluster sample

Step-by-step explanation:

A cluster sample occurs when the intended population is divided into   non- overlapping sub -groups or clusters and some of these clusters are represented in the sample.

From the question, In a state 15 high schools where randomly selected and  the standardized test was administered to only 10th grade student. Here, the  high schools  are the non-overlapping sub groups that is randomly selected and a reasonable representation of the  entire subgroups.