A university's mathematics department has designed an extension program to encouragenew undergraduate students to pursue careers in mathematics. The program consists ofadditional advanced classes that focus on the various applications of mathematics indifferent industries. To determine which students will be invited to this extensionprogram, new undergraduate mathematics students are all required to take an'entrance" exam. Any student that scores higher than 80 on the exam will be invited tothe extension program. Suppose that scores in this entrance exam are normallydistributed with mean 61 and variance 256. Assume that scores are independent fromstudent to student.in a random sample of 12 new undergraduate mathematics students who took theentrance exam, find the probability that more than 2 will be invited to the extensionprogram.
Question
A university's mathematics department has designed an extension program to encouragenew undergraduate students to pursue careers in mathematics. The program consists ofadditional advanced classes that focus on the various applications of mathematics indifferent industries. To determine which students will be invited to this extensionprogram, new undergraduate mathematics students are all required to take an'entrance" exam. Any student that scores higher than 80 on the exam will be invited tothe extension program. Suppose that scores in this entrance exam are normallydistributed with mean 61 and variance 256. Assume that scores are independent fromstudent to student.in a random sample of 12 new undergraduate mathematics students who took theentrance exam, find the probability that more than 2 will be invited to the extensionprogram.
Solution 1
First, we need to find the z-score for a score of 80 on the exam. The z-score is calculated as:
Z = (X - μ) / σ
where X is the score, μ is the mean, and σ is the standard deviation. The standard deviation is the square root of the variance, so σ = √256 = 16.
So, the z-score for a score of 80 is:
Z = (80 - 61) / 16 = 1.1875
Next, we look up this z-score in a standard normal distribution table or use a calculator to find the corresponding probability. The probability that a student scores 80 or higher (i.e., the probability that a student is invited to the extension program) is 1 - P(Z < 1.1875) ≈ 1 - 0.8820 = 0.1180.
Now, we want to find the probability that more than 2 out of 12 students are invited to the extension program. This is a binomial problem, where the number of trials is 12, the number of successes is 3 (since we want more than 2), and the probability of success on each trial is 0.1180.
The probability that exactly k students are invited to the program is given by the binomial probability formula:
P(X = k) = C(n, k) * (p^k) * ((1 - p)^(n - k))
where C(n, k) is the number of combinations of n items taken k at a time, p is the probability of success, and n is the number of trials.
We want the probability that more than 2 students are invited, so we need to calculate 1 - P(X = 0) - P(X = 1) - P(X = 2).
Using a calculator or statistical software to calculate these probabilities and subtract from 1, we find that the probability that more than 2 out of 12 students are invited to the extension program is approximately 0.891.
Solution 2
First, we need to find the z-score for a score of 80 on the exam. The z-score is calculated as:
Z = (X - μ) / σ
where X is the score, μ is the mean, and σ is the standard deviation. The standard deviation is the square root of the variance, so σ = √256 = 16.
So, the z-score for a score of 80 is:
Z = (80 - 61) / 16 = 1.1875
Next, we look up this z-score in a standard normal distribution table or use a calculator to find the corresponding probability. The probability that a student scores 80 or higher (i.e., the probability that a student is invited to the extension program) is 1 - P(Z < 1.1875) ≈ 1 - 0.8820 = 0.1180.
Now, we want to find the probability that more than 2 out of 12 students are invited to the extension program. This is a binomial problem, where the number of trials is 12, the number of successes is 3 (since we want more than 2), and the probability of success on each trial is 0.1180.
The probability that exactly k students are invited to the program is given by the binomial probability formula:
P(X = k) = C(n, k) * (p^k) * ((1 - p)^(n - k))
where C(n, k) is the number of combinations of n items taken k at a time, p is the probability of success, and n is the number of trials.
We want the probability that more than 2 students are invited, so we need to calculate 1 - P(X = 0) - P(X = 1) - P(X = 2).
Using a calculator or statistical software to calculate these probabilities and subtract from 1, we find that the probability that more than 2 out of 12 students are invited to the extension program is approximately 0.891.
Solution 3
First, we need to find the z-score for a score of 80 on the exam. The z-score is calculated as:
Z = (X - μ) / σ
where X is the score, μ is the mean, and σ is the standard deviation. The standard deviation is the square root of the variance, so σ = √256 = 16.
So, the z-score for a score of 80 is:
Z = (80 - 61) / 16 = 1.1875
Next, we look up this z-score in a standard normal distribution table or use a calculator to find the corresponding probability. The probability that a student scores 80 or higher (i.e., the probability that a student is invited to the extension program) is 1 - P(Z < 1.1875) ≈ 1 - 0.8820 = 0.1180.
Now, we want to find the probability that more than 2 out of 12 students are invited to the extension program. This is a binomial problem, where the number of trials is 12, the number of successes is 3 (since we want more than 2), and the probability of success on each trial is 0.1180.
The probability that exactly k students are invited to the program is given by the binomial probability formula:
P(X = k) = C(n, k) * (p^k) * ((1 - p)^(n - k))
where C(n, k) is the number of combinations of n items taken k at a time, p is the probability of success, and n is the number of trials.
We want the probability that more than 2 students are invited, so we need to calculate 1 - P(X = 0) - P(X = 1) - P(X = 2).
Using a calculator or statistical software to calculate these probabilities and subtract from 1, we find that the probability that more than 2 out of 12 students are invited to the extension program is approximately 0.891.
Similar Questions
A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 5.50. A sample of 37 honors students is taken and is found to have a mean GPA equal to 5.60. The population standard deviation is assumed to equal 0.40. The parameter to be tested is __________
The final exam scores in a statistics class were normally distributed with a mean of 63 and a standard deviation of five. Find the probability that a randomly selected student scored more than 68 on the exam. (3 marks)
From the past experience, a professor knows that the test score of a student taking his/herfinal exam is a random variable with mean 75 and variance 25. What can be said aboutthe probability that a student will score between 65 and 85.
5A certain college randomly selected 30 freshman students who completed college algebra during their first semester. Fifteen students were chosen from students who took the course at night and 15 students were chosen from students who took the course during the day. The following statistical information was calculated from their final grades. Day NightMean 76 68Median 68 72Mode 64 72Range 38 53Based on these samples, what generalization can be made? (Assume that a score of 70 or greater is a passing score.) A. The median score for the day students was higher than the median score for the night students. B. The range of scores was larger for the day students than for the night students. C. The mean score for the night students was higher than the mean score for the day students. D. The mean score for the day students was higher than the mean score for the night students.
3) Suppose the test scores on the APU entrance exam is normally distributed with a meanof 70 and a standard deviation of 15.(i) What proportion of students scored between 60 and 85.(ii) What proportion of students scored above 9(iii) What proportion of students scored less than 50
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.