Final answer:
The correct answer is 'd. Average, pattern,' where variables tend to fluctuate around the mean, creating a pattern. The mean is a key measure of central tendency, often used alongside median and mode, and standard deviation measures the spread of data around the mean. Option d.
Step-by-step explanation:
Values of variables fluctuate around the mean to establish a pattern of values. The answer to the student's question is 'd. Average, pattern.'
The mean, which is also called the average, is a measure of central tendency that describes the center of the data set. It can be influenced by outliers or extreme values, hence other measures like median and mode are also used when assessing the center of a data set.
While the median is best used when there are outliers, the mode indicates the most frequently occurring value or values in the case of bimodal or multimodal distributions.
To calculate the mean, add together all of the data values and divide by the number of data points. If the data set consists of ranges, a midpoint can be estimated by adding the lower and upper boundaries and dividing by two, and then calculating the weighted mean.
The spread of data, or the variation, is commonly measured by the standard deviation, which indicates how far data values are from the mean. Option d.