the meaning of standard deviationWatch
for example, a low s.d. means that each value is close to the mean, but a high sd means that they are very spread out.
it's basically a measure of spread.
hope this helps!
i think i know to get the st dev (good old excel) but what does that mean? i know it has something to do with the mean and normal distribution, but aprt from that im stuck. thx, xx
68% of the people in the population for whatever you're researching into will fall within one standard deviation either side of the mean in a normal distribution.
Extend it to two SDs either side, and you push it up to 95%.
99.8% of the population should fall within 3 SDs.