1. Measures of spread: range, variance & standard deviation
Sal discusses the three most common measures of spread!
2. Variance of a population
Variance as a measure of, on average, how far the data points in a population are from the population mean
3. Sample variance
Thinking about how we can estimate the variance of a population by looking at the data in a sample.
4. Review and intuition why we divide by n-1 for the unbiased sample variance
Reviewing the population mean, sample mean, population variance, sample variance and building an intuition for why we divide by n-1 for the unbiased sample variance
5. Simulation showing bias in sample variance
Simulation by Peter Collingridge giving us a better understanding of why we divide by (n-1) when calculating the unbiased sample variance. Simulation available at: http://www.khanacademy.org/cs/challenge-unbiased-estimate-of-population-variance/1169428428
7. Why we divide by n - 1 in variance
Another visualization providing evidence that dividing by n-1 truly gives an unbiased estimate of population variance. Simulation at: http://www.khanacademy.org/cs/unbiased-variance-visualization/1167453164
8. Simulation providing evidence that (n-1) gives us unbiased estimate
Simulation by KA user tetef showing that dividing by (n-1) gives us an unbiased estimate of population variance. Simulation at: http://www.khanacademy.org/cs/will-it-converge-towards-1/1167579097
12. The idea of spread and standard deviation
See how distributions that are more spread out have a greater standard deviation.
14. Concept check: Standard deviation
Six questions that will help you understand standard deviation more deeply.
15. Sample standard deviation and bias
Sals shows an example of calculating standard deviation and bias.
16. Statistics: Standard deviation
Review of what we've learned. Introduction to the standard deviation.
19. Statistics: Alternate variance formulas
Sal explains a different variance formula and why it works!
Current time: 0:00Total duration: 13:07
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Review of what we've learned. Introduction to the standard deviation. Created by Sal Khan.