Can someone check? thanks
Head lice can be a problem in classrooms. From the past experience, suppose it is predicted that 5% of the students will get lice if there are some reported cases. The health nurse checks 120 randomly chosen students and records the number of students that have head lice. What is the probability that exactly 6, 7, 8 students in the random sample have head ice?”
p(k)= nCk P^k (1-p)^n-k
were
n= 120
p=0.05
k= 6,7,8
q= 1-0.05= 0.95
so:
p(k) = 120C6 x (0.05)^6 (0.95) ^120-6
p (k) = .1647898425
7:
p(k) = 120C7 x (0.05)^7 (0.95) ^120-7
p (k) = .1412484364
8:
p(k) = 120C8 x (0.05)^8 (0.95) ^120-8
p (k) = .1050070613
p(6) + p(7) + p(8)
= 0.410453403
is this correct?
Head lice can be a problem in classrooms. From the past experience, suppose it is predicted that 5% of the students will get lice if there are some reported cases. The health nurse checks 120 randomly chosen students and records the number of students that have head lice. What is the probability that exactly 6, 7, 8 students in the random sample have head ice?”
p(k)= nCk P^k (1-p)^n-k
were
n= 120
p=0.05
k= 6,7,8
q= 1-0.05= 0.95
so:
p(k) = 120C6 x (0.05)^6 (0.95) ^120-6
p (k) = .1647898425
7:
p(k) = 120C7 x (0.05)^7 (0.95) ^120-7
p (k) = .1412484364
8:
p(k) = 120C8 x (0.05)^8 (0.95) ^120-8
p (k) = .1050070613
p(6) + p(7) + p(8)
= 0.410453403
is this correct?