Timeline for Finding the Mean and Variance from PDF
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Jun 11, 2020 at 14:32 | history | edited | CommunityBot |
Commonmark migration
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| Jan 30, 2019 at 15:10 | comment | added | John Smith Optional | How do you obtain the equalities: $E[(X-\mu)^2] = \int_{-\infty}^{\infty}{(x-\mu)^2 f(x) dx}$ and $E[X^2] = \int_{-\infty}^{\infty}{x^2 f(x) dx}$ Can you point me to a proof of this, or to the property of integrals that is used to prove this? | |
| Jan 16, 2015 at 14:41 | vote | accept | Raptors1102 | ||
| Jan 16, 2015 at 14:41 | vote | accept | Raptors1102 | ||
| Jan 16, 2015 at 14:41 | |||||
| Jan 15, 2015 at 17:10 | comment | added | mugen | @Raptors1102 if you can't work out the integrals, just show us where you got stuck and I or someone else will help you sort this out. | |
| Jan 15, 2015 at 17:09 | comment | added | mugen | @wolfies OP said he integrated his pdf to compute the mean, I don't see why he wouldn't be able to compute the variance. Often at introductory level, it's more difficult to lay out a mathematical problem than to resolve it. | |
| Jan 15, 2015 at 17:02 | comment | added | wolfies | You provide a very helpful and 101 intro to calculating the first two moments of a distribution. But, given that the OP does not know how to calculate a variance or a mean, do you think it is realistic to expect him to be able to compute the integrals required here, which are not exactly 101, unless we do impose $\theta = 4$? If the person asks: Q. How can I get to the moon? A. Build a space shuttle. If you have any problems, please let me know where you got stuck. | |
| Jan 14, 2015 at 23:55 | history | answered | mugen | CC BY-SA 3.0 |