for Engineers 7th edition - Douglas C. Montgomery,
George C.Runger
,
, CHAPTER 2
Section 2-1
Provide a reasonable description of the sample space for each of the random experiments in Exercises 2.1.1 to 2.1.11.
There can be more than one acceptable interpretation of each experiment. Describe any assumptions you make.
2.1.1. Each of four transmitted bits is classified as either in error or not in error.
Let e and o denote a bit in error and not in error (o denotes okay), respectively.
S=¿ {e ,eo
,oe ,o e , ¿}{e
o ,eo ,oe ,o e
, ¿} {e o ,eo e
,oe ,o e, } ¿{}
2.1.2. The number of hits (views) is recorded at a high-volume Web site in a day.
}
S={0,1,2,... = set of nonnegative integers
2.1.3. In the final inspection of electronic power supplies, either units pass, or three types of nonconformities might occur:
functional, minor, or cosmetic. Three units are inspected.
Let a denote an acceptable power supply.
Let f, m, and c denote a power supply that has a functional, minor, or cosmetic error, respectively.
S={a,f ,m,c}
, 2.1.4. An ammeter that displays three digits is used to measure current in milliamperes.
A vector with three components can describe the three digits of the ammeter. Each digit can be 0,1,2,...,9.
The sample space S is 1000 possible three digit integers, S={000,001,...,999}
2.1.5. The following two questions appear on an employee survey questionnaire. Each answer is chosen from the five
point scale 1 (never), 2, 3, 4, 5 (always).
Is the corporation willing to listen to and fairly evaluate new ideas?
How often are my coworkers important in my overall job performance?
Let an ordered pair of numbers, such as 43 denote the response on the first and second question.
Then, S consists of the 25 ordered pairs
2.1.6. The time until a service transaction is requested of a computer to the nearest millisecond. S={0,1,2,...,} in
milliseconds
2.1.7. The pH reading of a water sample to the nearest tenth of a unit. S={1.0,1.1,1.2,…14.0}
2.1.8. The voids in a ferrite slab are classified as small, medium, or large. The number of voids in each category is
measured by an optical inspection of a sample.
Let s, m, and l denote small, medium, and large, respectively. Then S = {s, m, l, ss, sm, sl, ….}
2.1.9. A sampled injection-molded part could have been produced in either one of two presses and in any one of the eight
cavities in each press.
2.1.10. An order for an automobile can specify either an automatic or a standard transmission, either with or without air
conditioning, and with any one of the four colors red, blue, black, or white. Describe the set of possible orders for
this experiment.
2.1.11. Calls are repeatedly placed to a busy phone line until a connection is achieved.
Let c and b denote connect and busy, respectively. Then S = {c, bc, bbc, bbbc, bbbbc, …}