Question 1142050
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Given information:
{{{n = 10}}} is the number of trials
{{{p = 0.2}}} is the probability of success


First compute the mean mu
{{{mu = n*p}}}
{{{mu = 10*0.2}}}
{{{mu = 2}}}


and the standard deviation sigma
{{{sigma = sqrt(n*p*(1-p))}}}
{{{sigma = sqrt(10*0.2*(1-0.2))}}}
{{{sigma = 1.26491106406736}}} (approximate)


Now compute the lower and upper boundaries (L and U)
{{{L = mu - 2.5*sigma}}} 
{{{L = 2 - 2.5*1.26491106406736}}}
{{{L = -1.1622776601684}}}
{{{L = -1.16}}}


{{{U = mu + 2.5*sigma}}} 
{{{U = 2 + 2.5*1.26491106406736}}}
{{{U = 5.1622776601684}}}
{{{U = 5.16}}}


The results we got were: {{{L = -1.16}}} and {{{U = 5.16}}}


Let x = number of successes


If x > 5, then this is beyond the upper boundary {{{U = 5.16}}} since x is a positive whole number.


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<font size=4 color=red>Answer: It <u>is unusual</u> to have more than 5 successes.</font>
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