What is the mean and variance of X?
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 This topic has 9 replies, 4 voices, and was last updated 12 years, 11 months ago by Darth.

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February 8, 2009 at 4:14 pm #51818
I am double checking my work.
Does nay one know what the following would be?
In a survey,85% of voters support referendum.If 10 voters are chosen at random,and X is the number of voters that support this referendum, find the mean and variance of X?0February 8, 2009 at 7:00 pm #180834X~B(n,p)
E(X)=np
V(X)=npq0February 8, 2009 at 8:19 pm #180835In a survey,85% of voters support referendum.If 10 voters are chosen at random,and X is the number of voters that support this referendum, find the mean and variance of X?
0February 8, 2009 at 8:33 pm #180837TIG, START DOING YOUR OWN HOMEWORK AND STOP POSTING YOUR HOMEWORK QUESTIONS HERE!! THERE IS SOMETHING INHERENTLY DISHONEST ABOUT HAVING OTHERS DO YOUR HOMEWORK. START STUDYING!!!!!
0February 8, 2009 at 9:00 pm #180839I already did it. I was just checking to see if I am correct.
0February 8, 2009 at 10:11 pm #180841Yeah, I’m sure. How about next time you post your answer and then get confirmation.
0February 9, 2009 at 1:13 am #180845The binomial distribution has the following properties:
The mean of the distribution (ìx) is equal to n * P .
The variance (ó2x) is n * P * ( 1 – P ).
The standard deviation (óx) is sqrt[ n * P * ( 1 – P ) ].0February 9, 2009 at 1:29 am #180846The answer I had was mean 8.5 and variance was 1.275
I do not think this was correct. Is there another one you would like me to post my answer to?
I never had statistics in my life and this is only my 4 time in the class
so I would like to know I am on the right page.
I have no one to help me so that is why I was looking for help. I think I am in wrong place.0February 9, 2009 at 3:41 am #180848I don’t mean to be harsh with you and I feel badly that you may not have resources where ever you are but if we answered ever post from a student not able to do his/her homework this site would be full of such things. This site was founded to exchange information regarding Lean Six Sigma and not as a tutoring site for students. Here is the stated purpose of the Forum:This discussion forum covers the full range of Six Sigma Quality discourse and provides a fascinating look at evolving viewpoints, debate and advice on every subject from performing a 2 sample ttest to leading a Six Sigma deployment.
0February 9, 2009 at 3:45 am #180849And yes, according to the help provided by Helper, your answer is correct.
0 
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