An instructor who taught two sections of engineering statistics last term, the f

Question

An instructor who taught two sections of engineering statistics last term, the first with 25 students and the second with 40, decided to assign a term project. After all projects had been turned in, the instructor randomly ordered them before grading. Consider the first 15 graded projects. (a) What is the probability that exactly 10 of these are from the second section? (b) What is the probability that at least 10 of these are from the second section? (c) What is the probability that at least 10 of these are from the same section? (d) What are the mean value and standard deviation of the number among these 15 that are from the second section? mean projects standard deviation projects (e) What are the mean value and standard deviation of the number of projects not among these first 15 that are from the second section? mean projects standard deviation projects

Explanation / Answer

The random variable X is a hypergeometric random variable with parameters:

N = 65 = the total number of objects in the population, (i.e. the students)

M = 40 = the total number of “successes” in the population, in this case the number of students from the second class

n = 15 = the number of objects sampled in this case the number of graded exams

V(x)= (n*M/N) (1 – M/N)(N – n/ N – 1)=2.77367

So SD(x)=sqrt(V(x))=1.66543

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.