Final answer:
The answer involves matching descriptions to various statistical measures. For example, calculating the mean involves summing all values and dividing by the total count, which is a measure of the center. Other measures such as the range and interquartile range describe variation in the dataset.
Step-by-step explanation:
When Nina finds the difference between the least and greatest values, this is a measure of variation known as the range. So the correct assignment for description 1 would be a measure of variation. When she adds all the values and divides the sum by 5, she is calculating the mean which is a measure of center. For description 2, when Nina finds the mean and then the average deviation of the weights from the mean, she calculates what is known as the mean absolute deviation, a measure of variation. Description 3 relates to the interquartile range (IQR), which is the difference between the upper and lower quartiles and is also a measure of variation. The value that appeared most often, described in number 4, is the mode, a measure of center. Lastly, description 5 pertains to finding the median, and the middle value after arranging all weights in order, which is a measure of center as well.
As such, the answer would be:
• a. measures of center: 1 (mean), 4 (mode), 5 (median)
• b. measures of variation: 2 (mean absolute deviation), 3 (interquartile range)
It is important to remember that measures of center and measures of variation provide essential summaries of a dataset, with the mean, median, and mode summarizing the typical values, while the range, mean absolute deviation, and interquartile range provide insight into the spread or variability of the data.