TABLE OF CONTENTS Results from an experiment are usually reported as the average of several individual tests. The arithmetic mean, or average, x is defined as
where N is the number of measurements and the values of x i are the individual values of each measurement. A median value can also be determined for the data set x i. If the data are ordered in increasing value, the median is defined as the middle value for an odd number of results or as the average of the two middle values for an even number of results. A normal, or Gaussian, distribution will produce a median equal to the average.
In reporting experimental results, the level of confidence is conveyed by the number of significant figures used to report the data. Using more significant figures than is justified by the actual measurements or precision of the measuring system will lead to an erroneous impression of the accuracy. Thus, the number of significant figures should be no greater than that used in measuring the original data.
It is also important to avoid ambiguity in the number of significant figures. Scientific notation can effectively be used to avoid possible confusion. For example, if a number is written as 33,500, the number of significant figures could be three, four, or five. However, using scientific notation and writing the number as 3.350 10 4 indicates that there are four significant figures and that the true value is...
