Statistical Calculator Guide: Mean, Median, Standard Deviation
Statistics calculators handle calculations that are tedious by hand. Here is what each common statistic means and when to use it. Statistics calculators handle calculations that are tedious to do by hand: mean, median, standard deviation, correlation, and more. I use them regularly for analyzing data at work and for understanding the numbers in news reports. Here is a guide to what each common statistic means, when to use it, and the pitfalls I have learned to watch for. Mean and Median: When Each Is Appropriate The mean is the sum of all values divided by the count. The median is the middle value when the data is sorted. For a symmetric distribution, they are nearly identical. For skewed data, they can differ dramatically. The median household income in the United States is lower than the mean because a small number of very high earners pull the mean upward. When I see an average reported in the news, I check whether it is the mean or the median, because the mean can mislead when the data is skewed. Data: 30, 35, 40, 45, 200 Mean: (30+35+40+45+200) / 5 = 70 Median: 40 (middle value) Add a 6th value of 50: Sorted: 30, 35, 40, 45, 50, 200 Median = average of 40 and 45 = 42.5 Mean = (30+35+40+45+50+200) / 6 = 66.