Unformatted text preview: 28 CHAPTER 2 PROBABILITY When probability is discussed in this chapter, the probability of an event is determined as the ratio
,3 of the number of outcomes in the event to the number of outcomes in the sample space (for equally likely
3 outcomes). Therefore, the probability that a sample contains exactly two defective parts is 15,890,700 _ 0 535,095
— 0.034 ~ Note that this example illustrates a common distribution studied in Chapter 3 (hypergeometric distribution). EXERCISES FOR SECTION 2—1 Provide a reasonable description of the sample space for each
of the random experiments in Exercises 21 to 218. There can
be more than one acceptable interpretation of each experi
ment. Describe any assumptions you make. 2—1. Each of three machined parts is classiﬁed as either
above or below the target speciﬁcation for the part. 2—2. Each of four transmitted bits is classiﬁed as either in
error or not in error. 2—3. In the ﬁnal inspection of electronic power supplies,
three types of nonconformities might occur: functional, minor,
or cosmetic. Power supplies that are defective are further clas
siﬁed as to type of nonconformity. 2—4. In the manufacturing of digital recording tape, elec—
tronic testing is used to record the number of bits in error in a
350foot reel. 25. In the manufacturing of digital recording tape, each of
24 tracks is classiﬁed as containing or not containing one or
more bits in error. 26. An ammeter that displays three digits is used to meas
ure current in milliamperes. 2—7. A scale that displays two decimal places is used to
measure material feeds in a chemical plant in tons. 2—8. 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 oﬁen are my coworkers important in my overall job
performance? 29. The concentration of ozone to the nearest part per billion. 2‘10. The time until a service transaction is requested of a
computer to the nearest millisecond. 2‘1 1. The pH reading of a water sample to the nearest tenth
of a unit.
2,12. 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. 2—13. The time of a chemical reaction is recorded to the
nearest millisecond. 2.18. 2—14. An order for an automobile can specify either an
automatic or a standard transmission, either with or without air
conditioning, and any one of the four colors red, blue, black or
white. Describe the set of possible orders for this experiment. 2—15. A sampled injectionmolded part could have been
produced in either one of two presses and in any one of the
eight cavities in each press. 2—16. An order for a computer system can specify memory
of 4, 8, or 12 gigabytes, and disk storage of 200, 300, or 400
gigabytes. Describe the set of possible orders. « 2—17. Calls are repeatedly placed to a busy phone line until
a connect is achieved. In a magnetic storage device, three attempts are made
to read data before an error recovery procedure that reposi
tions the magnetic head is used. The error recovery procedure
attempts three repositionings before an “abort” message is
sent to the operator. Let s denote the success of a read operation f denote the failure of a read operation F denote the failure of an error recovery procedure
S denote the success of an error recovery procedure
A denote an abort message sent to the operator. Describe the sample space of this experiment with a tree diagram. 2—19. Three events are shown on the Venn diagram in the
following ﬁgure: Reproduce the ﬁgure and shade the region that corresponds to
each of the following events. (a) A’ (b) A {'1 B (d) (B U C)’ (e) (A F) B)’ U C (c) (AF‘IB)UC ...
View
Full Document
 Spring '08
 Wherly
 Statistics

Click to edit the document details