Question 59558
Find the margin of error that correspond to the given values of n(times) and x( successes) and the degree of confidence:n=1400,x=420 and 95%.

So, za/2 * square root of (pq/n)
 
    =  1.96 sqrt[(.3)(.7)/1400]
    =  1.96 sqrt[0.012247...)
    = 1.96*0.1107
    =0.21697
    =0.217 (answer to 3 decimal places of precision)
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However, if the result had been 0.000294 and you were told
to answer to 3 decimal places, the answer would have to be 
0.0
Cheers,
Stan H.