Questions 9,10,11,12,13,14,15
A person's blood glucose level and diabetes are closely related. Let x be a random variable measured in milligrams of glucose per deciliter (1/10 of a liter) of blood. Suppose that after a 12-hour fast, the random variable x will have a distribution that is approximately normal with mean u = 83 and standard deviation o = 19, Note: After 50 years of age, both the mean and standard deviation tend to increase. For an adult (under 50) after a 12-hour fast, find the following probabilities, a. x is less than 110 b. x is more than 60 c. x is greater than 140 d. x is between 60 and 110 10 Police response time to an emergency call is the difference between the time the call is first received by the dispatcher and the time a patrol car radios that it has arrived at the scene. Over a long period of time, it has been determined that the police response time has a normal distribution with a mean of 8.4 minutes and a standard deviation of 2.0 minutes. For a randomly received emergency call, find th following probabilities. (Round your answers to four decimal places.) a. The response time is between 7 and 10 minutes b. The response time is more than 9 minutes 11. Quick Start Company makes 12-volt car batteries. After many years of product testing, the company knows that the Alt average life of a Quick Start battery is normally distributed, with a mean of 47 months and a standard deviation of 7 months. If Quick Start guarantees a full refund on any battery that fails within the 35-month period after purchase, what percentage of its batteries will the company expect to replace? (Round your answer to two decimal places.) 12 The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 1260 chips and a standard deviation of 115 chips. a. Determine the 25th percentile for the number of chocolate chips in a bag b. Determine the number of chocolate chips in a bag that make up the middle 95% of bags. The time required for an automotive center to complete an oil change service on an automobile approximately follows a normal distribution, with a mean of 17 minutes and a stan minutes. nd a standard deviation of 2.1 a. The automotive center guarantees customers that the service will take no longer than 19 minutes. If it does take longer, the customer will receive the service for half-price, wh the service for half-price? If-price. What percent of customers receive b. If the automotive center does not want to give the discount to more than 4% of its customers, how long should it make the guaranteed time limit? 14 Quick Start Company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a Quick Start battery is normally distributed, with a mean of 47.0 months and a standard deviation of 7.1 months. If Quick Start does not want to make refunds for more than 10% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries (to the nearest month)? 15 There are two college entrance exams that are often taken by students, Exam A and Exam B. The composite score on Exam A is approximately normally distributed with mean 20.2 and standard deviation 5.4. The composite score on Exam B is approximately normally distributed with mean 1035 and standard deviation 210. Suppose you scored 35 on Exam A and 1510 on Exam B. Did you score better in exam A or exam B
