Of the pupils in a school, 30% travel to school by bus. From a sample...

realenishb0

Answered question

2022-02-14

Of the pupils in a school, $30\mathrm{\%}$ travel to school by bus. From a sample of 10 pupils chosen at random, what is the probability that more than 8 travel by bus?

Answer & Explanation

Nathen Wilkerson

Beginner2022-02-15Added 4 answers

Step 1
We have a binomial probability. I like to start these kinds of questions with this relation:
$\sum _{k=0}^{n}{C}_{n,\text{}k}{\left(p\right)}^{k}{(1-p)}^{n-k}=1$
We have $n=10,\text{}p=0.3$ adn are looking at $8<k\le 10$ ${C}_{10,\text{}9}{\left(0.3\right)}^{9}{\left(0.7\right)}^{1}+{C}_{10,\text{}10}{\left(0.3\right)}^{10}{\left(0.7\right)}^{0}\approx 0.00014$