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Math Help - Find the mean and standard deviation of the sum or difference of independent random v

  1. #1
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    Find the mean and standard deviation of the sum or difference of independent random v

    what should i do for A?? and for B, is it asking me to convert all the temperatures to Fahrenheit?
    Attached Thumbnails Attached Thumbnails Find the mean and standard deviation of the sum or difference of independent random v-screen-shot-2012-12-09-8.21.08-am.png   Find the mean and standard deviation of the sum or difference of independent random v-screen-shot-2012-12-09-8.21.19-am.png  
    Last edited by asilvester635; December 9th 2012 at 11:33 AM.
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  2. #2
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    Re: Find the mean and standard deviation of the sum or difference of independent rand

    They are asking for E[X-550], and \textrm{Var}(X-550). You should have some formulas that should make the preceding quite simple.
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  3. #3
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    Re: Find the mean and standard deviation of the sum or difference of independent rand

    yes i figured out how to get the mean... i just simply take the temperatures that are off target and minus it to 550... i got that part but what i don't know how to get is the standard deviation.... would you happen to know how to calculate that based on my problem??
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