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It is defined as the positive square root of the mean of the squared deviations from mean. The square of S.D is called variance.
The standard deviation is used as a measure of the variance of a measurement within a group of objects. In essence, it is the average difference between the measurement of any one object and the mean measurement for the group. For example, if the average measured weight of brown bears is 140kg (265lbs) and the standard deviation of weights among brown bears is 5kg (11lbs), then any particular, individual brown bear is likely to weight between 135-145kg (254-276lbs), and very likely to weight between 130-150kg (243-287lbs). It's impossible to know the weight of an individual bear just by looking at the mean weight for all bears, but the standard deviation tells you what range of weights the weight of an individual bear will fall in.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoI'm not 100% certain - I'm doing it in school and failing miserably - but it's a unit of measurement used to show how spread out the data is from the mean.
You'd need to ask on a maths forum to get something more detailed, though. Sorry.
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How many standard deviations is 16.50 from the mean?
How many standard deviations is 16.50 from the mean?
I have two data sets with the same number of values with means x1 and x2 and standard deviations of n1 and n2. How do you average means with standard deviations?
You can't average means with standard deviations. What are you trying to do with the two sets of data?
How many standard deviations is 19 from the mean?
That depends on what the standard deviation is.
How do you find two standard deviations above a mean?
It is mean + 2*standard deviation.
What does a z-score represent in terms of units?
standard deviations
How many standard deviations is 16.50 from the mean?
How many standard deviations is 16.50 from the mean?
What is the sum of the deviations from the mean?
The sum of standard deviations from the mean is the error.
What does normality mean in health and social care?
All minor deviations occurring with two standard deviations under the Gaussian curve are considered normal. Deviations occurring outside of two standard deviations are considered abnormal.
In a standard normal distribution 95 percent of the data is within plus standard deviations of the mean?
95% is within 2 standard deviations of the mean.
What is the standard deviation for Wechsler intelligence for children?
The mean for the WISC, like the WAIS, is 100. The deviations from 100, or standard deviations, are 15.
I have two data sets with the same number of values with means x1 and x2 and standard deviations of n1 and n2. How do you average means with standard deviations?
You can't average means with standard deviations. What are you trying to do with the two sets of data?
What is 2 standard deviations?
2 times the standard deviation!
What does STD devs stand for?
standard deviations
How many standard deviations is 19 from the mean?
That depends on what the standard deviation is.
This tells how many standard deviations a measurement is away from the mean?
Z-Score tells how many standard deviations a measurement is away from the mean.
What percentage of a normal distribution is within 2 standard deviations of the mean?
I believe the standard deviations are measured from the median, not the mean.1 Standard Deviation is 34% each side of median, so that is 68% total.2 Standard Deviations is 48% each side of median, so that is 96% total.
Can the standard deviation or variance be negative?
No, a standard deviation or variance does not have a negative sign. The reason for this is that the deviations from the mean are squared in the formula. Deviations are squared to get rid of signs. In Absolute mean deviation, sum of the deviations is taken ignoring the signs, but there is no justification for doing so. (deviations are not squared here)
