Question 675446


A)


E = (b-a)/2


E = (47.87 - 39.86)/2


E = 4.005


So the max error (E) is 4.005 (this is also called the margin of error)



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B)


E = C*s/sqrt(n)


4.005 = C*16.219/sqrt(63)


4.005*sqrt(63) = C*16.219


4.005*sqrt(63)/16.219 = C


C = 4.005*sqrt(63)/16.219


C = 1.959966


So the critical value is 1.959966, which means that the confidence level is 95% (use either a calculator or a table to find this)