Final answer:
To find the probability of selecting a ninth-grade student from a school population, divide the number of ninth-grade students by the total population.
Step-by-step explanation:
To find the probability that a randomly selected student is in the ninth-grade, we need to calculate the fraction of ninth-grade students out of the total population of students. Here's how:
- Add up the number of seventh, eighth, and ninth-grade students: 33 + 47 + 37 = 117.
- Divide the number of ninth-grade students by the total population: 37 / 117 = 0.316 (rounded to three decimal places).
The probability that the randomly selected student is in the ninth-grade is approximately 0.316, or 31.6%.