STA301 - Statistics and Probability Assignment No.2 Last date 07 February 2014

[vuassignments]

Assignment No: 2 (Lessons 27 – 30)

Question 1: Marks: 4+4=8

a) A batch of 10 gaskets contains 4 defective gaskets. If we draw samples of size 3 without replacement, from the batch of 10, find the probability that a sample contains 2 defective gaskets.

b) In a binomial distribution, the mean and the standard deviation were found to be 36 and 4.8 respectively. Find the parameters of binomial distribution.



Question 2: Marks: 4+3=7

It is known that the computer disks produced by a company are defective with probability 0.02 independently of each other. Disks are sold in packs of 10. A money back guarantee is offered if a pack contains more than 1 defective disk. What is the probability of sales result in the customers getting their money back?
The average number of accidents occurring in an industrial plant during a day is 3. Assuming Poisson distribution for the number of accidents (X) during a day, compute probability that at most two accidents occur in a day.

[vuassignments]

a) A batch of 10 gaskets contains 4 defective gaskets. If we draw samples of size 3 without replacement, from the batch of 10, find the probability that a sample contains 2 defective gaskets.

Solution

A batch of 10 rocker cover gaskets contains 4 defective gaskets. If we draw samples
of size 3 without replacement, from the batch of 10, find the probability
that a sample contains 2 defective gaskets.


  1.jpg (Size: 21.05 KB / Downloads: 1,429)

It is possible to derive formulae for the mean and variance of the Hypergeometric distribution.
However, the calculations are more difficult than their Binomial counterparts, so we will simple
state the results.