Back
to top
statistics
Watch
Announcements
Page 1 of 1
Go to first unread
Skip to page:
All students in a particular school study math, for which the failure rate is 20%. Assuming that the number of students who fail math follows a binomial distribution, for a class
of nine students, calculate
(i) the variance for the number of persons who failed maths in the class
[2 marks]
(ii) the probability that exactly two students failed maths
he probability that at least three students failed maths
of nine students, calculate
(i) the variance for the number of persons who failed maths in the class
[2 marks]
(ii) the probability that exactly two students failed maths
he probability that at least three students failed maths
0
reply
Report
#2
Most of this should be textbook
i. variance = np(1-p)
ii. P(X=2) using (n r)(p^r)(1-p)^(n-r)
iii. P(x=>3) = 1- P(x<3) using the binomial distribution (or you can san 1 - P(X=<2)).
Personally I can't understand why the failure rate of a math test would follow a binomial distribution, but there you go.
i. variance = np(1-p)
ii. P(X=2) using (n r)(p^r)(1-p)^(n-r)
iii. P(x=>3) = 1- P(x<3) using the binomial distribution (or you can san 1 - P(X=<2)).
Personally I can't understand why the failure rate of a math test would follow a binomial distribution, but there you go.
2
reply
X
Page 1 of 1
Go to first unread
Skip to page:
Quick Reply
