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.
How many standard deviations is 16.50 from the mean?
You can't average means with standard deviations. What are you trying to do with the two sets of data?
The z-score of a value indicates how many standard deviations it is from the mean. If a value is 2.08 standard deviations greater than the mean, its z-score is simply 2.08. This means the value lies 2.08 standard deviations above the average of the dataset.
That depends on what the standard deviation is.
In a normal distribution, approximately 68% of scores fall within one standard deviation of the mean (between -1 and +1 standard deviations). About 95% of scores fall within two standard deviations (between -2 and +2 standard deviations). Therefore, the percentage of scores that falls specifically between the mean and -2 to 2 standard deviations is about 95% minus the 50% that is below the mean, resulting in approximately 45%.
How many standard deviations is 16.50 from the mean?
The sum of standard deviations from the mean is the error.
95% is within 2 standard deviations of the mean.
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.
The mean for the WISC, like the WAIS, is 100. The deviations from 100, or standard deviations, are 15.
2 times the standard deviation!
You can't average means with standard deviations. What are you trying to do with the two sets of data?
The z-score of a value indicates how many standard deviations it is from the mean. If a value is 2.08 standard deviations greater than the mean, its z-score is simply 2.08. This means the value lies 2.08 standard deviations above the average of the dataset.
That depends on what the standard deviation is.
standard deviations
In a normal distribution, approximately 68% of scores fall within one standard deviation of the mean (between -1 and +1 standard deviations). About 95% of scores fall within two standard deviations (between -2 and +2 standard deviations). Therefore, the percentage of scores that falls specifically between the mean and -2 to 2 standard deviations is about 95% minus the 50% that is below the mean, resulting in approximately 45%.
Z-Score tells how many standard deviations a measurement is away from the mean.