A sample study of 642 people discovered that 514 people have a high school diploma.

If a person is chosen at random, the likelihood that the person has a high school diploma is:

The total number of people we have given is 642. It was also discovered that 514 people have a high school diploma. As a result, this is a positive outcome. To find the desired result, we will use the formula 

$P\left(E\right)=\frac{\text{ favourable outcome }}{\text{ total number of outcome }}$

Given that:

Total number of people $n( \mathrm{S})=642$

No. of peoples having high school certificate $n\left(E\right)=514$

$\mathrm{P}\left(\mathrm{E}\right)=$ Probability that the person has a school certificate

$\therefore \mathrm{P}\left(\mathrm{E}\right)=\frac{\mathrm{n}\left(\mathrm{E}\right)}{\mathrm{n}\left(\mathrm{S}\right)}=\frac{514}{642}=0.8006$