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Both are measures of the spread of the data around a mean or average. In fact the standard deviation == sqrt(variance). The standard deviation (SD) is defined to be the square root of the sample variance (V).
EX: Some value X = M +/- 1 SD indicates that there is roughly a 2/3 probability that the value will fall randomly within the interval from minus one SD up to plus one SD around the mean M.
What else can I help you with?
What do you mean when you say that the coefficient of variation has no units?
Suppose the mean of a sample is 1.72 metres, and the standard deviation of the sample is 3.44 metres. (Notice that the sample mean and the standard deviation will always have the same units.) Then the coefficient of variation will be 1.72 metres / 3.44 metres = 0.5. The units in the mean and standard deviation 'cancel out'-always.
What does it mean for a sample to have a standard deviation of zero?
It means that there are is no variation from the mean. In other words, all values in your sample are identical.
What is the sample standard deviation of 27.5?
A single observation cannot have a sample standard deviation.
Is sample standard deviation the same as standard deviation?
No, the standard deviation is a measure of the entire population. The sample standard deviation is an unbiased estimator of the population. It is different in notation and is written as 's' as opposed to the greek letter sigma. Mathematically the difference is a factor of n/(n-1) in the variance of the sample. As you can see the value is greater than 1 so it will increase the value you get for your sample mean. Essentially, this covers for the fact that you are unlikely to obtain the full population variation when you sample.
What does the sample standard deviation best estimate?
The standard deviation of the population. the standard deviation of the population.
What does it mean when the standard error value is smaller than the standard deviation?
It simply means that you have a sample with a smaller variation than the population itself. In the case of random sample, it is possible.
Can a standard deviation of a sample be equal to a standard deviation of a population?
Yes
How do i find sample standard deviation from population standard deviation?
If the population standard deviation is sigma, then the estimate for the sample standard error for a sample of size n, is s = sigma*sqrt[n/(n-1)]
Can standard deviation be zero?
Yes, but only in the case where all numbers in your sample are the same. If you attempt to use a zero standard deviation in most statistical analyses, you will get an error message. Your sample has shown no variation so no inferences can be made to the general population.
How does one calculate the standard error of the sample mean?
Standard error of the sample mean is calculated dividing the the sample estimate of population standard deviation ("sample standard deviation") by the square root of sample size.
What is the statistic that is used to estimate a population standard deviation?
the sample standard deviation
The variation in the population as measured by the standard deviation has little or no effect in determining the size of a sample selected from the population True or False?
The answer is False
