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12.4
The Standard Deviation will give you an idea of how 'spread apart' the data is. Suppose the average gasoline prices in your town are 2.75 per gallon. A low standard deviation means many of the gas stations will have prices close to that price, while a high standard deviation means you would find prices much higher and also much lower than that average price.
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.
Yes, I have suppose that. Then what?
Suppose you have n observations {x1, x2, ... , xn} for a variable, X. Calculate m = (x1 + x2 + , ... , + xn)/n, the mean value. Calculate s2 = (x12 + x22 + , ... , + xn2)/n Then Variance = s2 - m2 = [mean of the squares] - [square of the mean] and the standard deviation = sqrt(Variance)
0.84
probability is 43.3%
12.4
64.
13.1 squared = 3.62
Standard deviation is the square root of the variance; so if the variance is 64, the std dev is 8.
Standard deviation is a measure of the scatter or dispersion of the data. Two sets of data can have the same mean, but different standard deviations. The dataset with the higher standard deviation will generally have values that are more scattered. We generally look at the standard deviation in relation to the mean. If the standard deviation is much smaller than the mean, we may consider that the data has low dipersion. If the standard deviation is much higher than the mean, it may indicate the dataset has high dispersion A second cause is an outlier, a value that is very different from the data. Sometimes it is a mistake. I will give you an example. Suppose I am measuring people's height, and I record all data in meters, except on height which I record in millimeters- 1000 times higher. This may cause an erroneous mean and standard deviation to be calculated.
Variance is 362 or 1296.
It would be approximately normal with a mean of 2.02 dollars and a standard error of 3.00 dollars.
The Standard Deviation will give you an idea of how 'spread apart' the data is. Suppose the average gasoline prices in your town are 2.75 per gallon. A low standard deviation means many of the gas stations will have prices close to that price, while a high standard deviation means you would find prices much higher and also much lower than that average price.
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.
Suppose you conduct an experiment that yields a collection of pairs, (x1, y1), (x2, y2), (x3, y3), ... (xn, yn). In other words, yi is the value of variable y when variable x assumes the value xi. Let us call the average of the xi values x-bar and the average of the yi values y-bar. Then an x-deviation is xi - x-bar and a y-deviation is yi - y-bar. One product of a pair of these deviations is ( xi - x-bar )( yi - y-bar ). If you now sum these deviations with the i going from 1 to n you will have the 'sum of the product of the deviations'.