Reference no: EM132409403

These questions are to help assist me with other questions. They do not involve the same numbers. I am trying to see how to work them out.

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 μ = 83 and standard deviation σ = 21. 

x is more than 60

x is less than 110

x is between 60 and 110

x is greater than 125 (borderline diabetes starts at 125)

Porphyrin is a pigment in blood protoplasm and other body fluids that is significant in body energy and storage. Let x be a random variable that represents the number of milligrams of porphyrin per deciliter of blood. In healthy circles, x is approximately normally distributed with mean μ = 43 and standard deviation σ = 12. Find probabilities.

x is less than 60

x is greater than 16

x is between 16 and 60

x is more than 60 (This may indicate an infection, anemia, or another type of illness.)

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 46.6 months and a standard deviation of 7.1 months.

(a) If Quick Start guarantees a full refund on any battery that fails within the 36-month period after purchase, what percentage of its batteries will the company expect to replace?

(b) If Quick Start does not want to make refunds for more than 9% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries (to the nearest month)?