Question 78:

Asked on January 23, 2008

1

Answer:

No answer provided yet.The standard deviation (SD for short) tells you how much the data vary around the mean. For example, the data-points 25, 26, 29, 31 have a mean of 27.75 and a SD of 2.75. The data-points 1, 4, 6, 100 also have a mean of 27.75 but have a standard deviation of 48.2. That much higher SD (20 times larger than the 1st) tells you the data is much more variable.

With only four data-points you can quickly see the 100 stands out in comparison to the other values. The SD summarizes the variability for you .