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ikky101
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ikky101
Of 500 students in a high school, 72 % have indicated that they are interested in attending college. What is the probability of selecting a random sample of 50 students wherein the sample proportion indicating interest in college is greater than 80 %?

Responding to a pm:

Total 500 students.
72% of 500 = 360
360 interested in attending college
140 not interested

We need to randomly select 50 students such that 41/42/43... /50 are interested in going to college. So our favourable cases will be the following:
Case 1: Select 41 students from the 360 who want to attend college and rest 9 from those 140 who don't. The % who want to attend college will be 41/50 = 82% here (higher than 80%)
Case 2: Select 42 students from the 360 who want to attend college and rest 8 from those 140 who don't. The % who want to attend college will be 42/50 = 84% here (higher than 80%)
and so on...

Favourable cases = 360C41 * 140C9 + 360C42 * 140C8 + ... + 360C50

Total cases = 500C50

Required Probability = Favourable cases/Total cases
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