A sample proportion is the percent of a surveyed group with a particular trait. If that group was selected at random, its proportion can estimate the proportion in the whole population. Apply the sample percent to the whole population, not to the sample size. Then type the percent-of expression into Desmos. The result is an estimate, not an exact count.
Hints
- Hint 1
A random sample is a smaller group selected by chance from a larger group. Its support percentage can estimate the support percentage among all the teachers. How many teachers are at the school?
- Hint 2
A percent needs a base: the whole group you're taking a part of. You're estimating a count for the entire school, so which number belongs after “of”: the number surveyed or the school total?
Step-by-step
Apply the sample percent to the school total
Step 1Transfer the sample rate
The surveyed teachers are the sample, the smaller group measured. Because they were selected at random from the school, their support rate can estimate the rate for the population, all the school's teachers. It doesn't mean the population rate is known exactly.
- Step 2
Choose the base for the percent
The question asks for a count among all teachers, so use the school total as the base:
Taking of would count supporters in the sample, not estimate the count across the school.
- Step 3
Calculate the estimate
Type in Desmos. It prints , so the best estimate is teachers who support adding the annual field trip. Choice C.