Qnt_Week_1_Exercizes

Exercise 80 (Ch. 3) Explain why the times are a population. The wait times are a population because it represents a relevant variable with a tangible data set, i.e. we can manipulate the data to make determinations. Find the mean and median of the times. The mean of a population is defined as the sum of all the values in a population divided by the total number of values in the population. Sum = 1021 minutes Number of values = 25 Mean = 40.85 minutes The median of a population is the midpoint of the values after they have been ordered from the smallest to largest or the largest to the smallest. Median = 39 minutes Find the range and the standard deviation of the times. The range is the minimum to maximum values of a data set. Range = 23 – 67 minutes The standard deviation is the square root of the variance, which is the arithmetic mean of the squared deviations from the mean [pic] Exercise 36 (Ch. 5) Given: 80% of students will complete assigned problems 90% of students completing problems will pass the course 60% of students not completing problems will pass the course Mike took the course last semester and received a passing grade Find: The probability that Mike completed the assignments. Solution: We are already given the solution to the question: “What is the probability that Mike passed the course”, which can be rephrased as “What is the probability of passing the course.” This solution would require the analysis of the events: 1. Completed assignments and passed 2. Did not complete assignments and passed Since the information is provided, the perception of the probability for Mike is 1. We know that Mike passed. The probability determination can be reworded as: 1. Given a passing grade, what is the probability of the event: completed assignments' This means that the probability determination is entirely dependent on the given statement: 1. 80% (0.8) of students will complete assigned problems This means that the probability that Mike completed the assignments is 0.8. Exercise 45 (Ch. 6) Given: Machine is producing 10% defective pieces Find: In a sample of 10 pieces a. Exactly 5 will be defective b. 5 or more will be defective Solution: a. Exercises 42 and 45 (Ch. 7)