Q.1 a) Each sample of water has a 10% chance of containing a particular organic

pollutant. Assume that the samples are independent with regard to the presence of

the pollutant.

i. Find the probability exactly 2 contains the pollutant in the next 18 samples.

ii. Determine the probability that at-least 4 samples contain the pollutant.

iii. Determine the probability b/w 3 and 7 (Both inclusive) contain pollutant.

b) Contamination is a problem in the manufacture of optical storage disks (CDs).

The number of particles of contamination that occur on an optical disk has a

Poisson distribution, and the average number of particles per centimeter squared

of media surface is 0.1. The area of disk under study is 100 squared centimeters.

i. Find the probability that 12 particles occur in the area of disk under study.

ii. Determine the probability Zero particles occur in the area of disk under study