What are the corresponding trimming percentages? (round your answers to two decimal places.)

Statistics Problems 1

Sec 1.3

…………………………………………………………………………………………

Top of Form

1. –/15 points DevoreStat9 1.E.034.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

Total

–/15

Exposure to microbial products, especially endotoxin, may have an impact on vulnerability to allergic diseases. The following are data on concentration (EU/mg) in settled dust for one sample of urban homes and another of farm homes.

U:

6.0

5.0

11.0

33.0

4.0

5.0

80.0

18.0

35.0

17.0

23.0

F:

3.0

16.0

11.0

9.0

6.0

9.0

2.0

17.0

3.0

7.9

23.0

9.9

4.0

2.0

0.8

(a) Determine the sample mean for each sample. (Round your answers to two decimal places.)

urban homes

1 EU/mg

farm homes

2 EU/mg

How do they compare?

The average endotoxin concentration is about the same in both urban and farm homes. The average endotoxin concentration in farm homes is more than double the average concentration in urban homes. The average endotoxin concentration in urban homes is more than double the average concentration in farm homes.

(b) Determine the sample median for each sample.

urban homes

4 EU/mg

farm homes

5 EU/mg

How do they compare?

The median endotoxin concentration is about the same in both urban and farm homes. The median endotoxin concentration in farm homes is roughly double the median concentration in urban homes. The median endotoxin concentration in urban homes is roughly double the median concentration in farm homes.

Why is the median for the urban sample so different from the mean for that sample?

The mean and median for urban homes are so different because the measure different aspects of the distribution. The mean and median for urban homes are so different because there are fewer observations. The mean and median for urban homes are so different because the few large values raise the mean but not the median.

(c) Calculate the trimmed mean for each sample by deleting the smallest and largest observation. (Round your answers to two decimal places.)

urban homes

8 EU/mg

farm homes

9 EU/mg

What are the corresponding trimming percentages? (Round your answers to two decimal places.)

urban homes

10 %

farm homes

11 %

How do the values of these trimmed means compare to the corresponding means and medians? Urban homes:

The trimmed mean is 12 the mean of the entire sample. The trimmed mean is 13 the median of the entire sample.

Farm homes:

The trimmed mean is 14 the mean of the entire sample. The trimmed mean is 15 the median of the entire sample.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

2. –/6 points DevoreStat9 1.E.504.XP.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

5

6

–/1

–/1

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

0/5

0/5

Total

–/6

The minimum injection pressure (psi) for injection molding specimens of high amylose corn was determined for eight different specimens (higher pressure corresponds to greater processing difficulty), resulting in the following observations.

14.6

12.5

17.5

14.2

12.0

10.9

9.5

8.0

(a) Determine the values of the sample mean x, sample median x tilde, and 12.5% trimmed mean xtr. (Round your answers to two decimal places.)

x

= 1 psi

x tilde

= 2 psi

xtr

= 3 psi

Compare these values.

The mean is much larger than the median and trimmed mean, indicating positive skewness. The mean is much larger than the median and trimmed mean, indicating negative skewness. All three measures of center are similar, indicating little skewness to the data set. The median is much larger than the mean and trimmed mean, indicating negative skewness. The median is much larger than the mean and trimmed mean, indicating positive skewness.

(b) By how much could the smallest sample observation, currently 8.0, be increased without affecting the value of the sample median? 5 psi (c) Suppose we want the values of the sample mean and median when the observations are expressed in kilograms per square inch (ksi) rather than psi. Is it necessary to reexpress each observation in ksi, or can the values calculated in part (a) be used directly? [Hint: 1 kg = 2.2 lb.]

Yes, it is necessary to reexpress each observation. No, the values obtained in part (a) can be used directly.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

3. –/18 points DevoreStat9 1.E.036.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

Total

–/18

A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) to complete the escape:

380

350

356

360

378

424

323

397

401

374

374

370

364

368

364

327

338

394

392

369

377

359

352

407

332

398

(a) Construct a stem-and-leaf display of the data. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.)

Stems

Leaves

32

1

33

2

34

3

35

4

36

5

37

6

38

7

39

8

40

9

41

10

42

11

How does it suggest that the sample mean and median will compare?

The display is reasonably symmetric, so the mean and median will be close. The display is positively skewed, so the median will be greater than the mean. The display is positively skewed, so the mean will be greater than the median. The display is negatively skewed, so the median will be greater than the mean. The display is negatively skewed, so the mean will be greater than the median.

(b) Calculate the values of the sample mean x and median x tilde. [Hint: Σxi = 9628.] (Round your answers to two decimal places.)

x =

13 sec

x tilde=

14 sec

(c) By how much could the largest time, currently 424, be increased without affecting the value of the sample median? (Enter ∞ if there is no limit to the amount.)

By how much could this value be decreased without affecting the value of the sample median? (Enter ∞ if there is no limit to the amount.)

(d) What are the values of x and x tildewhen the observations are reexpressed in minutes? (Round your answers to two decimal places.)

x

= 17 min

x tilde

= 18 min

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

4. –/1 points DevoreStat9 1.E.037.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

–/1

0/5

Total

–/1

The article "Snow Cover and Temperature Relationships in North America and Eurasia"† used statistical techniques to relate the amount of snow cover on each continent to average continental temperature. Data presented there included the following ten observations on October snow cover for Eurasia during the years 1970-1979 (in million km2):

6.5 12.0 14.9 10.0 10.7 7.9 21.9 12.5 14.5 9.2

What would you report as a representative, or typical, value of October snow cover for this period, and what prompted your choice?

The mean of this sample because the mean is always the best central measure. The mean of this sample because a potential outlier may produce a misleading median. The median of this sample because the median is always the best central measure. The median of this sample because a potential outlier may produce a misleading mean.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

5. –/3 points DevoreStat9 1.E.038.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

–/1

–/1

–/1

0/5

0/5

0/5

Total

–/3

Blood pressure values are often reported to the nearest 5 mmHg (100, 105, 110, etc.). The actual blood pressure values for nine randomly selected individuals are given below.

108.6

117.4

128.4

120.0

103.7

112.0

98.3

121.5

123.2

(a) What is the median of the reported blood pressure values? 1 mmHg (b) Suppose the blood pressure of the second individual is 117.7 rather than 117.4 (a small change in a single value). What is the new median of the reported values? 2 mmHg What does this say about the sensitivity of the median to rounding or grouping in the data?

When there is rounding or grouping, the median is only sensitive to large changes. When there is rounding or grouping, the median is not sensitive to small changes. When there is rounding or grouping, the median can be highly sensitive to small change.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

6. –/3 points DevoreStat9 1.E.039.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

–/1

–/1

–/1

0/5

0/5

0/5

Total

–/3

The propagation of fatigue cracks in various aircraft parts has been the subject of extensive study in recent years. The accompanying data consists of propagation lives (flight hours/104) to reach a given crack size in fastener holes intended for use in military aircraft.

0.725

0.842

0.865

0.911

0.924

0.943

0.961

1.010

1.038

1.049

1.082

1.126

1.137

1.158

1.242

1.366

(a) Compute and compare the values of the sample mean x and median x tilde. (Round your answers to four decimal places.)

x

= 1 flight hours/104

x tilde

= 2 flight hours/104

(b) By how much could the largest sample observation be decreased without affecting the value of the median? (Enter your answer to three decimal places.) 3 flight hours/104

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

7. –/4 points DevoreStat9 1.E.041.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

Total

–/4

A sample of n = 10 automobiles was selected, and each was subjected to a 5-mph crash test. Denoting a car with no visible damage by S (for success) and a car with such damage by F, results were as follows:

S F F S S S F F S F

(a) What is the value of the sample proportion of successes x/n? 1 (b) Replace each S with a 1 and each F with a 0. Then calculate x for this numerically coded sample. x = 2 How does x compare with x/n?

The proportion in part (a) is exactly equal to the mean in part (b). The proportion in part (a) is greater than the mean in part (b). The proportion in part (a) is less than the mean in part (b).

(c) Suppose it is decided to include 15 more cars in the experiment. How many of these would have to be S's to give x/n = 0.72 for the entire sample of 25 cars? 4 cars

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

Home My Assignments Extension Request

Bottom of Form

WebAssign® 4.0 © 1997-

………………………………………………………………………………………….

Sec 1.4

…………………………………………………………………………………………..

Top of Form

1. 1/4 points | Previous Answers DevoreStat9 1.E.505.XP.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

1/1

0/1

–/1

–/1

1/5

1/5

0/5

0/5

Total

1/4

An article reported the following data on oxygen consumption (mL/kg/min) for a sample of ten firefighters performing a fire-suppression simulation:

28.9

49.1

30.1

28.5

28.4

25.5

33.7

29.3

23.3

31.1

Compute the following. (Round your answers to four decimal places.)

(a) The sample range 1 Correct: Your answer is correct.mL/kg/min (b) The sample variance s2 from the definition (i.e., by first computing deviations, then squaring them, etc.) 2 Incorrect: Your answer is incorrect.mL2/kg2/min2 (c) The sample standard deviation 3 mL/kg/min (d) s2 using the shortcut method 4 mL2/kg2/min2

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

2. –/11 points DevoreStat9 1.E.045.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

5

6

7

8

9

10

11

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

0/5

Total

–/11

Suppose the value of Young's modulus (GPa) was determined for cast plates consisting of certain intermetallic substrates, resulting in the following sample observations:

116.6

115.9

114.6

115.4

115.6

(a) Calculate x. 1 GPa Calculate the deviations from the mean. (Enter your answers to two decimal places.)

x

116.6

115.9

114.6

115.4

115.6

deviation

2

3

4

5

6

(b) Use the deviations calculated in part (a) to obtain the sample variance and the sample standard deviation. (Round your answers to three decimal places.)

s2

=

7 GPa2

s

=

8 GPa

(c) Calculate s2 by using the computational formula for the numerator Sxx. (Round your answer to three decimal places.) 9 GPa2 (d) Subtract 100 from each observation to obtain a sample of transformed values. Now calculate the sample variance of these transformed values. (Round your answer to three decimal places.) 10 GPa2 Compare it to s2 for the original data.

The variance in part (d) is greater than the variance in part (b). The variance in part (d) is equal to the variance in part (b). The variance in part (d) is smaller than the variance in part (b).

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

3. –/3 points DevoreStat9 1.E.506.XP.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

–/1

–/1

–/1

0/5

0/5

0/5

Total

–/3

The accompanying observations are on stabilized viscosity (cP) for specimens of a certain grade of asphalt with 18% rubber added:

2751

2909

3023

2800

2856

(a) What are the values of the sample mean x and sample median x tilde?

x =

1 cP

x tilde=

2 cP

(b) Calculate the sample variance using the computational formula. [Hint: First subtract a convenient number from each observation.] (Round your answer to the nearest whole number.) 3 cP2

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

4. –/4 points DevoreStat9 1.E.049.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

Total

–/4

A study of the relationship between age and various visual functions (such as acuity and depth perception) reported the following observations on the area of scleral lamina (mm2) from human optic nerve heads:

2.80

2.61

2.70

3.92

2.27

2.65

3.86

4.16

3.80

4.27

3.37

4.60

2.48

3.61

2.80

3.51

2.92

(a) Calculate Σxi and Σxi2. (Round Σxi2 to two decimal places.)

Σxi

= 1 mm2

Σxi2

= 2 mm4

(b) Use the values calculated in part (a) to compute the sample variance s2 and then the sample standard deviation s. (Round your answers to three decimal places.)

s2

= 3 mm4

s

= 4 mm2

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

5. –/1 points DevoreStat9 1.E.050.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

–/1

0/5

Total

–/1

A woman sued a computer keyboard manufacturer, charging that her repetitive stress injuries were caused by the keyboard. The injury awarded about $3.5 million for pain and suffering, but the court then set aside that award as being unreasonable compensation. In making this determination, the court identified a "normative" group of 27 similar cases and specified a reasonable award as one within two standard deviations of the mean of the awards in the 27 cases. The 27 awards were (in $1000s) 38, 61, 72, 112, 136, 143, 146, 151, 238, 290, 340, 410, 600, 750, 750, 750, 1050, 1100, 1136, 1150, 1200, 1200, 1250, 1578, 1700, 1825, and 2000, from which

Σxi = 20,176, Σxi2 = 24,656,604.

What is the maximum possible amount that could be awarded under the two-standard-deviation rule? (Round your answer to the nearest whole number.) 1 thousand dollars

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

6. –/4 points DevoreStat9 1.E.051.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

Total

–/4

An article reported the following data on oxidation-induction time (min) for various commercial oils:

85

104

130

160

180

195

131

145

213

105

145

152

151

136

87

99

91

119

129

(a) Calculate the sample variance and standard deviation. (Round your answers to three decimal places.)

s2

= 1 min2

s

= 2 min

(b) If the observations were reexpressed in hours, what would be the resulting values of the sample variance and sample standard deviation? Answer without actually performing the reexpression. (Round your answer to three decimal places.)

s2

= 3 hr2

s

= 4 hr

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

7. –/2 points DevoreStat9 1.E.052.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

–/1

–/1

0/5

0/5

Total

–/2

The first four deviations from the mean in a sample of n = 5 reaction times were 0.4, 0.9, 1.2, and 1.5. What is the fifth deviation from the mean? 1 Give a sample for which these are the five deviations from the mean.

−3.6, −3.1, −2.8, −2.5, −4

4.4, 4.9, 5.2, 5.5, 0

−0.6, −0.1, 0.2, 0.5, 0

1.4, −0.1, 2.2, 2.5, −5.0

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

8. –/1 points DevoreStat9 1.E.058.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

–/1

0/5

Total

–/1

A company utilizes two different machines to manufacture parts of a certain type. During a single shift, a sample of n = 20 parts produced by each machine is obtained, and the value of a particular critical dimension for each part is determined. The comparative boxplot below is constructed from the resulting data.

http://www.webassign.net/devorestat8/1-e-058.gif

Compare and contrast the two samples. (Select all that apply.)

A typical value is much larger for machine 1 than for machine 2.Machine 2's sample values have considerably more variation than machine 1's sample values.Machine 1's sample values have considerably more variation than does machine 2's sample values.A typical value seems to be about the same for the two machines.Machine 1 and machine 2's sample values have about the same amount of variation.The only outlier that exists is from machine 1.A typical value is much larger for machine 2 than for machine 1.The only outlier that exists is from machine 2.There are no outliers present.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

9. –/1 points DevoreStat9 1.E.060.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

–/1

0/5

Total

–/1

Observations on burst strength (lb/in2) were obtained both for test nozzle closure welds and for production canister nozzle welds.†

Test

7200

6100

7300

7300

8000

7400

7300

7300

8000

6700

8300

Cannister

5250

5625

5900

5900

5700

6050

5800

6000

5875

6100

5850

6600

A comparative boxplot is given below.

http://www.webassign.net/devorestat8/1-e-060-ism.gif

Comment on interesting features (the cited article did not include such a picture, but the authors commented that they had looked at one). (Select all that apply.)

The test nozzle welds have much more variable burst strengths.The production canister welds have much higher burst strengths.The test nozzle welds data contain 2 outliers.The production canister welds data contain 2 outliers.The production canister welds have consistently lower burst strengths than the test nozzle welds.The production canister welds have much more variable burst strengths.

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

Home My Assignments Extension Request

Bottom of Form

WebAssign® 4.0 © 1997-2017 Advanced

……………………………………………………………………………………………

Sec 2.2

…………………………………………………………………………………………..

Top of Form

Your last submission is used for your score.

1. –/4 points DevoreStat9 2.E.501.XP.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

Total

–/4

Consider randomly selecting a student at a certain university, and let A denote the event that the selected individual has a Visa credit card and B be the analogous event for a MasterCard. Suppose that P(A) = 0.3, P(B) = 0.5, and P(A ∩ B) = 0.25.

(a) Compute the probability that the selected individual has at least one of the two types of cards (i.e., the probability of the event A ∪ B). 1 (b) What is the probability that the selected individual has neither type of card? 2 (c) Describe, in terms of A and B, the event that the selected student has a Visa card but not a MasterCard.

A ∪ B'

A ∩ B'

A' ∩ B'

A' ∩ B

A' ∪ B'

Calculate the probability of this event. 4

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

2. –/2 points DevoreStat9 2.E.014.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

–/1

–/1

0/5

0/5

Total

–/2

Suppose that 45% of all adults regularly consume coffee, 65% regularly consume carbonated soda, and 75% regularly consume at least one of these two products.

(a) What is the probability that a randomly selected adult regularly consumes both coffee and soda? 1 (b) What is the probability that a randomly selected adult doesn't regularly consume at least one of these two products? 2

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

3. –/4 points DevoreStat9 2.E.016.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

Total

–/4

An individual is presented with three different glasses of cola, labeled C, D, and P. He is asked to taste all three and then list them in order of preference. Suppose the same cola has actually been put into all three glasses.

(a) What are the simple events in this ranking experiment? (Enter your answer in set notation.)

What probability would you assign to each one? 1 0ver 3 is 1/3

All of the simple events have the same probability,

1

3

.

All of the simple events have the same probability,

1

6

.

It is impossible to determine the probability of the simple events with the given information. The probability of an individual event where D is ranked first is

1

5

.

The probability of another individual event is

1

15

.

The probability of an individual event where D is ranked first is

1

12

.

The probability of another individual event is

1

4

.

(b) What is the probability that C is ranked first? (Round your answer to three decimal places.) 3 (c) What is the probability that C is ranked first and D is ranked last? (Round your answer to three decimal places.) 4

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

4. –/1 points DevoreStat9 2.E.502.XP.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

–/1

0/5

Total

–/1

A box contains six 40-W bulbs, four 60-W bulbs, and eight 75-W bulbs. If bulbs are selected one by one in random order, what is the probability that at least two bulbs must be selected to obtain one that is rated 75 W? (Round your answer to three decimal places.) 1

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

5. –/2 points DevoreStat9 2.E.019.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

–/1

–/1

0/5

0/5

Total

–/2

Human visual inspection of solder joints on printed circuit boards can be very subjective. Part of the problem stems from the numerous types of solder defects (e.g., pad non-wetting, knee visibility, voids) and even the degree to which a joint possesses one or more of these defects. Consequently, even highly trained inspectors can disagree on the disposition of a particular joint. In one batch of 10,000 joints, inspector A found 720 that were judged defective, inspector B found 756 such joints, and 1328 of the joints were judged defective by at least one of the inspectors. Suppose that one of the 10,000 joints is randomly selected.

(a) What is the probability that the selected joint was judged to be defective by neither of the two inspectors? (Enter your answer to four decimal places.) 1 (b) What is the probability that the selected joint was judged to be defective by inspector B but not by inspector A? (Enter your answer to four decimal places.) 2

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

6. –/3 points DevoreStat9 2.E.020.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

–/1

–/1

–/1

0/5

0/5

0/5

Total

–/3

A certain factory operates three different shifts. Over the last year, 200 accidents have occurred at the factory. Some of these can be attributed at least in part to unsafe working conditions, whereas the others are unrelated to working conditions. The accompanying table gives the percentage of accidents falling in each type of accident-shift category.

Unsafe Conditions

Unrelated to Conditions

Day

13%

32%

Shift

Swing

9%

13%

Night

2%

31%

Suppose one of the 200 accident reports is randomly selected from a file of reports, and the shift and type of accident are determined.

(a) What are the simple events? (Let S1, S2, and S3 represent the day, swing, and night shifts, respectively. Let C1 and C2 represent the unsafe conditions and unrelated to conditions, respectively. Enter your answer in set notation.)

(b) What is the probability that the selected accident was attributed to unsafe conditions? 2 (c) What is the probability that the selected accident did not occur on the day shift? 3

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

7. –/7 points DevoreStat9 2.E.021.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

4

5

6

7

–/1

–/1

–/1

–/1

–/1

–/1

–/1

0/5

0/5

0/5

0/5

0/5

0/5

0/5

Total

–/7

An insurance company offers four different deductible levels—none, low, medium, and high—for its homeowner's policyholders and three different levels—low, medium, and high—for its automobile policyholders. The accompanying table gives proportions for the various categories of policyholders who have both types of insurance. For example, the proportion of individuals with both low homeowner's deductible and low auto deductible is 0.07 (7% of all such individuals).

Homeowner's

Auto

N

L

M

H

L

0.04

0.07

0.05

0.04

M

0.07

0.10

0.20

0.08

H

0.02

0.03

0.15

0.15

Suppose an individual having both types of policies is randomly selected.

(a) What is the probability that the individual has a medium auto deductible and a high homeowner's deductible? 1 (b) What is the probability that the individual has a low auto deductible? A low homeowner's deductible?

auto deductible

2

homeowner's deductible

3

(c) What is the probability that the individual is in the same category for both auto and homeowner's deductibles? 4 (d) Based on your answer in part (c), what is the probability that the two categories are different? 5 (e) What is the probability that the individual has at least one low deductible level? 6 (f) Using the answer in part (e), what is the probability that neither deductible level is low? 7

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

8. –/3 points DevoreStat9 2.E.022.

Ask Your Teacher

Sent

My Notes

No response yet

There was an error sending your message.

Ask Your TeacherAsk Your Teacher Send

Question Part

Points

Submissions Used

1

2

3

–/1

–/1

–/1

0/5

0/5

0/5

Total

–/3

The route used by a certain motorist in commuting to work contains two intersections with traffic signals. The probability that he must stop at the first signal is 0.4, the analogous probability for the second signal is 0.45, and the probability that he must stop at at least one of the two signals is 0.5.

(a) What is the probability that he must stop at both signals? 1 (b) What is the probability that he must stop at the first signal but not at the second one? 2 (c) What is the probability that he must stop at exactly one signal? 3

Need Help? Read It0 Talk to a Tutor

Your work in question(s) will also be submitted or saved.

Viewing Saved Work Revert to Last Response

9. –/4 points DevoreStat9 2.E.026.