In City A, a law official has stated that 30% of items sold in any of the city’s
ID: 3312236 • Letter: I
Question
In City A, a law official has stated that 30% of items sold in any of the city’s pawn shops have come from stolen property. Our hero has purchased twenty-five (25) items from one of City A’s pawn shops. Let x = the number of these purchases that have been stolen. For this binomial distribution, find mean and standard deviation, and determine the answers to c, d & e using the charts in the textbook: (a) mean (b) standard deviation (c) probability that all of the 25 items were stolen (d) probability that at least 14 of the items were stolen (e) probability that at least 6 but no more 18 of the items were stolen.
Explanation / Answer
a) Mean = n*p =0.3 *25 = 7.5
b ) Sd = (npq)^0.5 = (0.3*0.7*25)^0.5 = 2.29
c)
<0.000000000001
d)
0.00599
e)
0.8065 -0.000018 = 0.8064