Question

In a particular university 40% of the students are having newspaper reading habit. Nine university students are selected to find their views on reading habit. Find the probability that all those selected have newspaper reading habit

Answer 1

Let p to the probability of having newspaper reading habit

p = `40/100 = 2/5`

q = 1 – p

= `1 2/5`

= `(5 - 2)/5`

= `3/5` and n = 9

In the binomial distribution p(x = 4) = nc_x p^xq^n-r 

The binomial distribution P(x) = `9"C"_x (2/5)^x (3/5)^(9 - x)`

P(all those selected have newspaper reading habit)

= `"P"("X" = 9)`

= `9"C"_9 (2/5)^9 (3/5)^(9 - 9)`

= `(1)(2/5)^9 (3/5)^0`

= `(2)^9/(5)^9`

= `512/1953125`

= 0.000262