![]() ![]() The averages will be different even if you haven’t changed anything. It might be higher than the first sample, it might be lower, but the likelihood that it will exactly the same is very, very small. If you take a second sample of data from an unchanged process and calculate that sample’s average, YOU WILL GET A DIFFERENT AVERAGE. Since you are (presumably) trying to improve the performance, you are trying to shift that mean – to change the average to a higher or lower value.īUT remember there is variation. So now you have an average (usually a mean) value. The more certain you want to be, the bigger sample you need. The move variation there is, the bigger sample you need to gain the same level of certainty (which is really expressed as the probability you are wrong). Take a big enough sample, and you can become reasonably confident that the average of your sample represents (meaning is close to) the average of everything. In spite of what I said above, there are occasions when using an average as a goal or as part of a target condition makes sense.Ī process running over time produces a range of values that fall into a distribution of some kind.Īny sample you take is just that – a sample. (If you understand elementary statistical testing you can skip this part… except I’ve experts who should have known better fall into the trap I am about to describe, so maybe you shouldn’t skip it after all.) And once that single number is calculated, the data are often thrown away.īe suspicious when you hear “averages” used as a performance measurement. ![]() It’s easier to put down a single number than to build a run chart and look at every data point. Why? Most people learned how to calculate an arithmetic mean in junior high school. The data here is contrived, but the example I am citing is something I have seen multiple times. I would have them measure hits and misses, not averages. In this case, the “average” really gives you almost no information. On the one below, 11 points miss the goalīut the both have an average 5 points over the goal. On the first one, 100% of the data points meet or exceed the goal of 15. Take a look at those two run charts below*. “Our goal is 15, and our average performance is 20.” In this example, if we exceed 15, we’re good. They simply dump all of their data into a simple arithmetic mean, and determine a score of sorts for how well the process is doing. The Problem with AveragesĪverages can be very useful when used as part of a rigorous statistical analysis. ![]() If you need to, you can adjust the column widths to see all the data.Īverage of the numbers in cells A2 through A6.Īverage of the numbers in cells A2 through A6 and the number 5.Īverage of the numbers in cells A2 through C2.As a general rule I strongly discourage the use of averages and “percent improvement” (or reduction) type metrics for process improvement. For formulas to show results, select them, press F2, and then press Enter. On the File tab, click Options, and then, in the Advanced category, look under Display options for this worksheet.Ĭopy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. To locate the Show a zero in cells that have a zero value check box: ![]() When this option is selected, empty cells are not counted, but zero values are. Tip: When you average cells, keep in mind the difference between empty cells and those containing the value zero, especially if you have cleared the Show a zero in cells that have a zero value check box in the Excel Options dialog box in the Excel desktop application. If you want to calculate the average of only the values that meet certain criteria, use the AVERAGEIF function or the AVERAGEIFS function. If you want to include logical values and text representations of numbers in a reference as part of the calculation, use the AVERAGEA function. If a range or cell reference argument contains text, logical values, or empty cells, those values are ignored however, cells with the value zero are included.Īrguments that are error values or text that cannot be translated into numbers cause errors. Logical values and text representations of numbers that you type directly into the list of arguments are not counted. Additional numbers, cell references or ranges for which you want the average, up to a maximum of 255.Īrguments can either be numbers or names, ranges, or cell references that contain numbers. The first number, cell reference, or range for which you want the average. The AVERAGE function syntax has the following arguments: For example, if the range A1:A20 contains numbers, the formula = AVERAGE( A1:A20) returns the average of those numbers. Returns the average (arithmetic mean) of the arguments. This article describes the formula syntax and usage of the AVERAGE function in Microsoft Excel. ![]()
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