A quality control engineer tests the quality of produced computers. Suppose that 5% of computers have defects and defects occur independently of each other. I need to find the probability that the engineer has to test at least 5 computers in order to find 2 defective ones.
I thought of it and came up with a solution though I'm not sure whether it's correct or not.
The probability of finding 2 defective is p=0.05∗0.05=0.025 P(T≥5)=1−[P(T=4)+P(T=3)+(T=2)]=1−[0.025∗(0.975)3+0.025∗(0.975)2+0.025∗(0.975)1]=1−[0.025∗0.975(1+0.975+(0.975)2)=0.9300442