It is observed that there will be 25 blood specimens of normal persons, if 100 blood samples are tested. If 10 specimens are sent to a laboratory for testing, then the probability of having at least two specimens of normal persons is

Step-by-step solution

The probability of selecting a normal specimen from a pool of 100 blood samples is 25 100 = 1 4 P = 1 4 q=1- 1 4 = 3 4 No. of trials = n =10 aligned & P(x 2)=1-P(x < 2) & =1-P(x=1)-P(x=0) & =1- ¹⁰ C₁ ( 1 4 )^1 ( 3 4 )^9- ¹⁰ C₀ ( 1 4 )^0 ( 3 4 )¹⁰ & =1- 13 4 ( 3 9 )^9 & P(x 2)=1- 13 4 ( 3 9 )^9 aligned