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For high school students graduating in \(2007,\) college admissions to the nation's most selective schools were the most competitive in memory. (The New York Times, "A Great Year for Ivy League Schools, but Not So Good for Applicants to Them," April 4,2007 ). Harvard accepted about \(9 \%\) of its applicants, Stanford \(10 \%,\) and Penn \(16 \% .\) Jorge has applied to all three. Assuming that he's a typical applicant, he figures that his chances of getting into both Harvard and Stanford must be about 0.9\%. a) How has he arrived at this conclusion? b) What additional assumption is he making? c) Do you agree with his conclusion?

Short Answer

Expert verified
Jorge assumed independent acceptance, calculated 0.9%, but this is doubtful as acceptances may not be independent.

Step by step solution

01

Understand Jorge's Assumption

Jorge assumes that his chances of getting into both Harvard and Stanford happen independently, which means that being accepted to one school does not affect the chances of being accepted to the other. This leads to the use of the probability formula for independent events.
02

Calculate Joint Probability

If events are independent, the probability of both occurring is the product of their individual probabilities. For Harvard and Stanford: \( P(\text{Harvard} \cap \text{Stanford}) = P(\text{Harvard}) \times P(\text{Stanford}) = 0.09 \times 0.10 = 0.009 \text{ (or 0.9\%)} \). Jorge arrived at his conclusion by calculating this product.
03

Evaluate the Assumption of Independence

Jorge is assuming that the acceptance decisions from Harvard and Stanford are independent of each other. However, this might not be true in real scenarios, as similar factors (e.g., Jorge's GPA, test scores, and overall application strength) may influence his application at both schools.
04

State if Agreement with Conclusion

Considering the assumption of independence may not be valid in reality for college applications, the conclusion that the probability of getting into both schools is exactly 0.9% might not be accurate. Jorge's calculation is mathematically correct under his assumption, but the assumption itself is questionable.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Independent Events
To understand independent events, imagine flipping two coins. The outcome of the first flip doesn't affect the outcome of the second. This concept applies to probability theory as well. If two events, like coin flips, are independent, one happening does not influence the chance of the other occurring. In Jorge's case, he assumes his acceptance to Harvard and Stanford are independent events, meaning that his applications are evaluated completely separately at both institutions.

In reality, independent events are rarer than you might think. Factors like talent or past achievements can influence multiple outcomes, making true independence difficult to achieve. It’s crucial to evaluate whether the assumption of independence makes sense in a given context.
Joint Probability
Joint probability involves calculating the likelihood of two or more events happening at the same time. When events are independent, the joint probability is simply the product of their separate probabilities. This means if Event A has a probability of 0.2 and Event B has a probability of 0.3, the joint probability of both events occurring is 0.2 multiplied by 0.3, equaling 0.06, or 6%.

For Jorge, the joint probability of getting into both Harvard and Stanford is the product of the probabilities of getting into each school: 9% for Harvard and 10% for Stanford. Thus, the probability of being admitted to both is 0.09 times 0.10, resulting in 0.009 or 0.9%. Understanding joint probability requires recognizing whether events are truly independent or not.
College Admissions
The college admissions process can be complex and multifaceted. Factors such as GPA, test scores, extracurricular activities, and recommendation letters all play a significant role in acceptance decisions. For top universities like Harvard and Stanford, the process is even more competitive, and the criteria can vary slightly from one school to another, even if they look similar at first glance.

Applicants need to be mindful that each application is assessed based on unique standards set by the institution. Despite commonalities, the evaluation mechanism can lead to potentially non-independent outcomes, which affects the probability calculations, as seen in Jorge's case. This intricacy can challenge assumptions around independent judgment in acceptances.
Assumption Evaluation
Evaluating assumptions is a crucial part of correctly assessing probabilities. In probability theory, as shown with Jorge's situation, an initial assumption (like independence of events) might simplify calculations but doesn't automatically reflect reality.

Additionally, it is essential to analyze what drives these assumptions. Are they based on valid evidence or merely convenience? In college admissions, numerous shared factors influence decisions across schools, suggesting that assuming independent events could misrepresent actual likelihoods. When assumptions are questionable, the ultimate probability results may also necessitate scrutiny. Setting realistic and evidence-backed assumptions ensures that calculated probabilities are more likely to align with real-world outcomes.

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