Expected value, variance, standard deviation (FREE STICKERS)

lands11

lands11

Active member
Ok NS so I have been asking for a ton of help on math problems lately. So since I really have appreciated it I will mail stickers to whoever can correctly answer this problem(s) first and show the steps.
Expected value, variance, and standard deviationI need to find all three for 1/9x^(2/3), 1≤x≤8. (that is 1 over 9x^(2/3))

Please show your steps as you go, thank you.

 
Expected value = integral from 1 to 8 - if you can't integrate this function, you deserve to fail so I'm not doing that part for you.

Variance = mean of the equare - square of the mean. So, square the whole function and integrate like you did above. Next, square the value you got from part 1, and subtract the two. Integration? See above.

Standard deviation = square root of the variance.

 
For expected value don't you need to put in an extra x at the beginning og the equation before you integrate?
 
In my book they keep multiplying the entire function by x, that's what is throwing me off. Here is an example in the book f(x)=(3/26)x^2 on [1/3) then when they start to find expected value then integrate x(3/26x^2)dx. Where did that x in the front come from?
 
Oh nice thanks man, well since you have helped me the most you can pm me your address and I'll send you some stickers. I have a shit ton, Saga die-cuts I think a few oakley die-cuts. Some black salomon die cuts oh and gold ones too. I have a shit ton
 
Don't sweat it. Remember when you go to find the variance don't forget to square 9x^(1/3). Since it's a simple function though, it won't significantly complicate the problem.

GL with summer school. I took Calc II in the summer years ago. It wasn't so bad.

Props for staying on the ball over the summer.
 
my dad whos a mathematician doesn't understand your questions. he put it in a graph with a curve and want to know if you want the value for 1.001-7.999. or the value of real numbers.
 
He's looking for the values of mean, variance, and standard deviation on the interval from 1 to 8 over all real numbers between the two, which is an infinitely large number of real numbers.
 
You must log in or register to reply here.
Back
Top