Question

The correct size of a nickel is 21.21 millimeters. Based on that, the data can be summarized into the following table:

	Too Small	Too Large	Total
Low Income	20	20	40
High Income	24	11	35
Total	44	31	75

c) If 5 children are chosen at random, the probability that at least one would draw the nickel too small is:

d) If 110 children are chosen at random, it would be unusual if more than [how many?] drew the nickel too small.

Answer 1

a)

proportion of all children that drew the nickel too small is: =44/75 =0.587

b)

P(X=5)=

(nCx)px(1−p)(n-x)    =

0.2556

c)

P(X>=1)=1-P(X<=0)=

1-∑x=0x-1   (nCx)px(q)(n-x) =

0.9996

d)

more than 81 drew the nickel too small (please try 82 if this comes wrong)