Finding the mean and standard deviation of a binomial random variable | AP Statistics | Khan Academy

Example showing how to find the mean and standard deviation of a binomial random variable.

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[Oxcilic]

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[jramz]

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[rasway]

I have been struggling with this for 2 days. lol. This video was very helpful, thanks a lot!!!

[toton]

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[momenabdelmotaal]

i think you might be saving my semester sir. <3

[gritred]

I have been using statistics for a long time but never, for some reason, had a chance to question what a standard deviation means (not how it is computed) when you have a binomial distribution. If a Standard deviation is .48 with a mean of .62 . What can I say about mean and standard deviation. I guess it is .62 are a yes in sample taken and 1 standard deviation is .48 which comes out as .14 to 1.1 positives at 1 sigma expected in a new run? 
Here is a whole number example: if(say 100 tosses) I had a mean of 50 tails and a standard deviation of 5...So a 1 sigma is 50 + - 5 so it follows that 45 to 55 tails can be expected in any new run. Anyone have an answer as to whether or not I am "on track" with my conclusion? I summarize that the standard deviation is actually (in my binomial problem)