Final answer:
The test grades can be described using the mean, median, and mode. The mean of the grades 87, 85, 85, and 82 is 84.75, the median and mode are both 85.
Step-by-step explanation:
The question asks us to describe the test grades using measures of center such as mean, median, and mode. The measures of center help summarize a set of data by identifying the central point around which the data is distributed. When we have test grades of 87, 85, 85, and 82, the mean (average) is calculated by adding all grades together and dividing by the number of grades. The median is the middle value when the numbers are put in order, and the mode is the most frequently occurring grade. In this case, the mean would be (87+85+85+82)/4 = 339/4 = 84.75, the median is the average of the two middle numbers (85 and 85), which is 85, and the mode is also 85 since it appears most frequently.