Precision means calculate mean and variance from pdf a measurement using a particular tool or implement produces similar results every single time it is used. For example, if you step on a scale five times in a row, a precise scale would give you the same weight each time.
In math and science, calculating precision is essential to determine if your tools and measurements work well enough to get good data. You can report precision of any data set using the range of values, the average deviation, or the standard deviation. Determine the highest measured value. It helps to begin by sorting your data in numerical order, from lowest to highest.
This will ensure that you do not miss any values. Then select the value at the end of the list. For example, suppose you are testing the precision of a scale, and you observe five measurements: 11, 13, 12, 14, 12. After sorting, these values are listed as 11, 12, 12, 13, 14. The highest measurement is 14.
Find the lowest measured value. Once your data has been sorted, finding the lowest value is as simple as looking at the beginning of the list. For the scale measurement data, the lowest value is 11. Subtract the lowest value from the highest. The range of a set of data is the difference between the highest and lowest measurements. Just subtract one from the other. Report the range as the precision.
When reporting data, it is important to let the readers know what you have measured. Because there are different measures of precision, you should specify what you are reporting. The mean is not actually part of calculating the range or precision, but it is generally the primary calculation for reporting the measured value. The mean is found by adding up the sum of the measured values and then dividing by the number of items in the group. Find the mean of the data. The average deviation is a more detailed measure of the precision of a group of measurements or experiment values.
The first step in finding the average deviation is to calculate the mean of the measured values. The mean is the sum of the values, divided by the number of measurements taken. For this example, use the same sample data as before. Assume that five measurements have been taken, 11, 13, 12, 14, and 12. Calculate the absolute deviation of each value from the mean.
For this calculation of precision, you need to determine how close each value is to the mean. To do this, subtract the mean from each number. For this measurement, it does not matter whether the value is above or below the mean. Subtract the numbers and just use the positive value of the result. This is also called the absolute value.