Question

At a certain bus station, 47% of all arrivals are late. Suppose a random

sample of 12 bus arrivals is examined. Using the binomial function, give the

probability

Answer 1

Complete question :

At a certain bus station, 47% of all arrivals are late. Suppose a random

sample of 12 bus arrivals is examined. Using the binomial function, give the probability of ;

Atleast 8 late arrivals 2) At most 4 late arrivals

Answer:

P(x >= 8) = 0.1411 ;

P(x ≤ 4) = 0.2570

Explanation:

Using the binomial probability distribution relation :

P(x =x) = nCx * p^x * (1 - p)^(n - x)

p = 47% = 0.47

1 - p = 0.53

n = 12

A.)

Atleast 8 late arrivals

P(x >= 8) :p(x = 8)+p(x =9)+p(x=10)+p(x=11)+p(x=12)

Using a binomial distribution calculator to save computation time :

P(x >= 8) = 0.141096

P(x >= 8) = 0.1411

B.)

P(x ≤ 4) = p(x=0)+p(x=1)+p(x=2)+p(x=3)+p(x=4)

Using a binomial probability calculator ;

P(x ≤ 4) = 0.25697

P(x ≤ 4) = 0.2570