Using proportions, the estimate of the population percentage of seniors that will say they are going to the graduation party is of 62.5%.
A proportion is a fraction of a total amount, and the measures are related using a rule of three. Due to this, relations between variables, either direct or inverse proportional, can be built to find the desired measures in the problem.
The estimate of a population proportion is the sample proportion. In this problem, the sample proportion is of 75 out of 120 students, hence:
p = 75/120 = 0.625 = 62.5%.
The estimate of the population percentage of seniors that will say they are going to the graduation party is of 62.5%.
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