One standard for admission to Redfield College is that the student must rank in the upper quartile of his or her graduating high school class. What is the minimal percentile rank of a successful applicant?

So the minimal percentile rank of a successfull applicant is 75th.

Step-by-step explanation:

The median separates the upper half from the lower half of a set. So 50% of the values in a data set lie at or below the median, and 50% lie at or above the median.

The first quartile (Q1) separates the lower 25% from the upper 75% of a set. So 25% of the values in a data set lie at or below the first quartile, and 75% of the values in a data set lie at or above the first quartile.

The third quartile (Q3) separates the lower 75% from the upper 25% of a set. So 75% of the values in a data set lie at or below the third quartile, and 25% of the values in a data set lie at or the third quartile. It is also called the upper quartile.

Definition of a percentile

When a value V is said to be in the xth percentile of a set, x% of the values in the set are lower than V and (100-x) % of the values in the set are higher than V.

The upper quartile is higher than 75% of the measures, that is, the 75th percentile.

So the minimal percentile rank of a successfull applicant is 75th.