Friday, July 24, 2009

Standard deviation and its link to strength of concrete

Standard deviation generally indicates the deviation of a set of variables from the mean value. The less the value of standard deviation is, the more the values are close together.

Also, a low value of standard deviation indicates more consistent results. On the other hand, higher values represent inconsistent results. The standard deviation is represented by a normal distribution curve, which is a bell shaped curve with the mean value at the apex and positive and negative infinities on either side. The area covered by the curve gives the percentage of samples within the range. We can determine the confidence level of a set of samples using the standard deviation.