Learn about mean, median, and mode with Khan Academy's comprehensive review of these fundamental concepts in statistics.
The mean (average) of a data set is found by adding all numbers in the data set and then dividing by the number of values in the set. The median is the middle value when a data set is ordered from least to greatest. The mode is the number that occurs most often in a data set.
Learn how to calculate the mean by walking through some basic examples & trying practice problems.
Practice calculating the mean (average) of a data set. The mean gives us a sense of the middle, or center, of the data.
Practice calculating and interpreting the mean and standard deviation of a discrete random variable.
Practice finding the median of a data set. Like the mean, the median gives us a sense of the middle, or center, of the data.
Mean absolute deviation (MAD) of a data set is the average distance between each data value and the mean. Mean absolute deviation is a way to describe variation in a data set. Mean absolute deviation helps us get a sense of how "spread out" the values in a data set are.
A confidence interval for a mean gives us a range of plausible values for the population mean. If a confidence interval does not include a particular value, we can say that it is not likely that the particular value is the true population mean. However, even if a particular value is within the interval, we shouldn't conclude that the population mean equals that specific value.