Final answer:
The portion of high school students achieving the recommended physical activity levels, according to provided data and relevant health guidelines, is less than 1/2. However, without specific adolescent guidelines, half of students meet some level of recommended activity based on exercise frequency alone.
Step-by-step explanation:
According to the information provided, it seems that 75 percent of students exercise for 60 minutes or less daily, and half of the students exercise between 20 to 60 minutes a day. Given the recommendation by the U.S. Department of Health and Human Services (HHS) for adults, which matches the moderate physical activity range as enough to garner health benefits, it can be inferred that the portion of high school students getting the recommended levels of physical activity is likely less than 1/2.
The data points you've provided do not offer a more precise answer to the question of what exact portion of high school students achieve the recommended activity levels. However, if we consider only the information about the frequency of exercise without the specific duration of exercise recommended by health guidelines, it would be reasonable to assume 1/2 of students, according to the provided data, are getting recommended levels of physical activity albeit the definition for 'recommended levels' can be different for adolescents compared to that of adults.