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At a university, the probability that an incoming freshman will graduate within four years is 0.654. what is the probability that at least 70 out of a group of 110 incoming freshman will graduate in four

years?

2 Answers

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Final answer:

The probability of at least 70 out of 110 incoming freshmen graduating in four years can be found using normal approximation to the binomial distribution since the sample size is large. First, calculate the mean and standard deviation for the binomial distribution, determine the z-score for 70, and then use standard normal distribution to find the associated probability.

Step-by-step explanation:

The question relates to the concept of probability within the field of Mathematics. Specifically, it deals with the probability of multiple independent events occurring, which can be described by the binomial distribution. The probability of an incoming freshman graduating within four years at a university is given as 0.654, and we want to find the probability that at least 70 out of 110 freshmen will graduate within this timeframe.

To calculate this, you would typically use the binomial probability formula or a binomial distribution table, which may not be practical here given the large sample size of 110. However, for large n (number of trials) and when the probability p is not too close to 0 or 1, the binomial distribution can be approximated by a normal distribution, a method known as normal approximation to binomial distribution. For this approximation, the mean (μ) is n*p and the standard deviation (σ) is sqrt(n*p*(1-p)). You would then find the z-score for 70 using the formula z = (X - μ) / σ, where X is the number of successes (70). Afterwards, you would use standard normal distribution tables or a calculator to find the probability corresponding to that z-score.

It is important to know whether the question asks for the probability of exactly 70 students graduating, or at least 70 students graduating. In this case, you are interested in 'at least' 70 students, so you would look for the cumulative probability of z and subtract it from 1.

User Michael Cramer
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Final Answer:

The probability that at least 70 out of a group of 110 incoming freshmen will graduate within four years is approximately 0.922.

Step-by-step explanation:

To calculate the probability of at least 70 freshmen out of 110 graduating within four years, we can use the binomial probability formula. The binomial distribution models situations with two possible outcomes, success or failure, in a fixed number of trials.

In this scenario, success is defined as a freshman graduating within four years, and the probability of success p is given as 0.654. The number of trialsn is 110, and we want to find the probability of at least 70 successes.

Using statistical software or a calculator, we can compute the cumulative probability of at least 70 successes out of 110 using the binomial distribution. The result, approximately 0.922, represents the likelihood that at least 70 freshmen will graduate within the specified time frame.

This high probability indicates a favorable outcome for the university, suggesting a strong likelihood that a significant portion of the incoming freshmen will successfully graduate within the stipulated four-year period.