Question

In: Statistics and Probability

A box contains 12 items of which 3 are defective. A sample of 3 items is selected from the box


A box contains 12 items of which 3 are defective. A sample of 3 items is selected from the box. Let X denotes the number of defective item in the sample. Find the probability distribution of X. 

Solutions

Expert Solution

Probability of being deefective=3/12=1/4=0.25

sample size,n=3

X=number of defective items in the sample

We can use binomial distribution for X,as probability of success is constant for each trial and trails are independent.

P(x=r)=3Cr*0.25r*(1-0.25)3-r

x p(x)
0 0.4219
1 0.4219
2 0.1406
3 0.0156

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