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Concept check: Standard deviation (article) | Khan Academy
Standard deviation involves adding and subtracting values at various steps in the calculation process. For example, the differences between each data point and the mean are calculated, …
Population standard deviation (video) | Khan Academy
It's a way of quantifying how spread out the data is from its mean. A small standard deviation means that the data points are generally close to the mean, while a large standard deviation …
Measures of spread: range, variance & standard deviation
The range is easy to calculate—it's the difference between the largest and smallest data points in a set. Standard deviation is the square root of the variance. Standard deviation is a measure …
Population and sample standard deviation review
The formula we use for standard deviation depends on whether the data is being considered a population of its own, or the data is a sample representing a larger population.
Statistics: Alternate variance formulas (video) | Khan Academy
Sal explains a different variance formula and why it works! For a population, the variance is calculated as σ² = ( Σ (x-μ)² ) / N. Another equivalent formula is σ² = ( (Σ x²) / N ) - μ². If we …
The idea of spread and standard deviation - Khan Academy
In population standard deviation is calculated using every individual from that population while in sample standard deviation we take specific number of individuals from the population.
Reference: Conditions for inference on a proportion (article) | Khan ...
While meeting the independence condition is necessary for using the standard deviation formula for the sample proportion, the other conditions (random and normal) are also important for the …
Normal distribution problems: Empirical rule - Khan Academy
The rule states that (approximately): - 68% of the data points will fall within one standard deviation of the mean. - 95% of the data points will fall within two standard deviations of the mean. - …
Variance of a population (video) | Khan Academy
The standard deviation (sigma) is a measure of how much the data is spread out around the mean, not a better guess as to what the mean should be. A small value of sigma indicates that …