# A company operates four machines during three shifts each day. from

Part 1 of 16 –

Question 1 of 23

1.0 Points

A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if the number of breakdowns is independent of the shift.

Machine

Shift

A

B

C

D

1

41

20

12

16

2

31

11

9

14

3

15

17

16

10

A.The number of breakdowns is dependent on the shift, because the test value 11.649 is less than the critical value of 12.592.

B.The claim that the number of breakdowns is independent of the shift cannot be rejected, because the test value 11.649 is less than the critical value of 12.592.

C.The number of breakdowns is dependent on the shift, because the p-value is .07.

D.The number of breakdowns is independent of the shift, because the test value 12.592 is greater than the critical value of 11.649.

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Question 2 of 23

1.0 Points

The chi-square goodness-of-fit test can be used to test for:

A.significance of sample statistics

B.difference between population means

C.difference between population variances

D.normality

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Part 2 of 16 –

Question 3 of 23

1.0 Points

A correlation value of zero indicates.

A.a strong linear relationship

B.a weak linear relationship

C.a perfect linear relationship

D.no linear relationship

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Question 4 of 23

1.0 Points

A single variable X can explain a large percentage of the variation in some other variable Y when the two variables are:

A.directly related

B.inversely related

C.highly correlated

D.mutually exclusive

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Question 5 of 23

1.0 Points

Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. Using that data, find the estimated regression equation which can be used to estimate the monthly rent for apartments in this neighborhood using size as the predictor variable.

Apartments.xlsx

A.f$hat{y}= f$ 197.12 + 2.065(size)

B.f$hat{y}= f$ 177.12 + 0.8500(size)

C.f$hat{y}= f$ 1.065 + 177.12(size)

D. f$hat{y}= f$ 177.12 + 1.065(size)

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Part 3 of 16 –

Question 6 of 23

1.0 Points

Serum ferritin is used in diagnosing iron deficiency. In a study conducted recently researchers discovered that in a sample of 28 elderly men the sample standard deviation of serum ferritin was 52.6 mg/L. For 26 younger men the sample standard deviation was 84.2 mg/L. At the .01 level of significance, do these data support the conclusion that the ferritin distribution in elderly men has a smaller variance than in younger men?

A.Yes, because the test value 2.56 is greater than the critical value 0.394

B.Yes, because the test value 2.56 is greater than the critical value of 2.54

C.No, because the test value 1.60 is less than the critical value of 2.54

D.Yes, because the test value 0.390 is less than the critical value 2.54

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Question 7 of 23

1.0 Points

Two teams of workers assemble automobile engines at a manufacturing plant in Michigan. A random sample of 145 assemblies from team 1 shows 15 unacceptable assemblies. A similar random sample of 125 assemblies from team 2 shows 8 unacceptable assemblies.

Is there sufficient evidence to conclude, at the 10% significance level, that the two teams differ with respect to their proportions of unacceptable assemblies?

A.No, since the test value exceeds the critical value

B.No, since the test value does not exceed the critical value

C.No, since the p-value is less than 0.10

D.Yes, since the p-value is greater than 0.10

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Part 4 of 16 –

Question 8 of 23

1.0 Points

If a teacher is trying to prove that a new method of teaching economics is more effective than a traditional one, he/she will conduct a:

A.point estimate of the population parameter

B.one-tailed test

C.confidence interval

D.two-tailed test

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Question 9 of 23

1.0 Points

A null hypothesis can only be rejected at the 5% significance level if and only if:

A.the null hypotheses includes sampling error

B.a 95% confidence interval does not include the hypothesized value of the parameter

C.the null hypothesis is biased

D.a 95% confidence interval includes the hypothesized value of the parameter

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Question 10 of 23

1.0 Points

You conduct a hypothesis test and you observe values for the sample mean and sample standard deviation when n = 25 that do not lead to the rejection of H0. You calculate a p-value of 0.0667. What will happen to the p-value if you observe the same sample mean and standard deviation for a sample size larger than 25?

A.The p – value stays the same

B.The p – value increases

C.The p – value decreases

D.The p – value may increase or decrease

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Part 5 of 16 –

Question 11 of 23

1.0 Points

In a study of elephants a researcher wishes to determine the average weight of a certain subspecies of elephants. From previous studies, the standard deviation of the weights of elephants in this subspecies is known to be 1500 pounds. How many elephants does the researcher need to weigh so that he can be 80% confident that the average weight of elephants in his sample is within 350 pounds of the true average weight for this subspecies?

A.50

B.31

C.39

D.166

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Question 12 of 23

1.0 Points

Compute f$P(t_{20}leq -0.95)f$ where t20 has a t-distribution with 20 degrees of freedom. A.0.1767

B.0.8233

C.0.6466

D.0.5334

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Part 6 of 16 –

Question 13 of 23

1.0 Points

The normal distribution is:

A.a binomial distribution with only one parameter

B.a discrete distribution

C.a density function of a discrete random variable

D.the single most important distribution in statistics

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Part 7 of 16 –

Question 14 of 23

1.0 Points

In a small town, 60% of the households have dogs. If 5 households are randomly selected, what is the probability that at least 4 of them have dogs?

A.0.259

B.0.337

C.3

D.0.8

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Part 8 of 16 –

Question 15 of 23

1.0 Points

If P(A) = P(A|B), then events A and B are said to be

A.exhaustive

B.mutually exclusive

C.complementary

D.independent

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Part 9 of 16 –

Question 16 of 23

3.0 Points

A sport preference poll yielded the following data for men and women. Use a 5% significance level and test to determine if sport preference and gender are independent.

Sport Preferences of Men and Women Basketball Football Soccer

Men 20 25 30 75

Women 18 12 15 45

38 37 45 120

What is the test value for this hypothesis test?

Answer:

What is the critical value for this hypothesis test?

Answer:

What is the conclusion for this hypothesis test? Choose one.

1. There is sufficient evidence to support the claim that one’s sport preference is dependent on one’s gender.

2. There is not sufficient evidence to support the claim that one’s sport preference is dependent on one’s gender.

Answer: Enter only a 1 or 2 for your answer.

Part 10 of 16 –

Question 17 of 23

1.0 Points

A company has observed that there is a linear relationship between indirect labor expense (ILE) , in dollars, and direct labor hours (DLH). Data for direct labor hours and indirect labor expense for 18 months are given in the file ILE_and_DLH.xlsx

Treating ILE as the response variable, use regression to fit a straight line to all 18 data points.

Based on your results, If direct labor hours (DLH) increases by one hour, the indirect labor expense (ILE), on average, increases by approximately how much?

Place your answer, rounded to 2 decimal places, in the blank. Do not use any stray punctuation marks or a dollar sign. For example, 34.56 would be a legitimate entry.

Part 11 of 16 –

Question 18 of 23

1.0 Points

Are America’s top chief executive officers (CEOs) really worth all that money? One way to answer this question is to look at the annual company percentage increase in revenue versus the CEO’s annual percentage salary increase in that same company. Suppose that a random sample of companies yielded the following data:

percent change for corporation 15 12 3 12 28 6 8 2

percent change for CEO 6 17 -4 12 32 -1 7 2

Do these data indicate that the population mean percentage increase in corporate revenue is greater than the population mean percentage increase in CEO salary? Use a 5% level of significance. What is the p-value associated with this test of hypothesis? Place your answer, rounded to 3 decimal places, in the blank. For example, 0.134 would be a legitimate entry.

Part 12 of 16 –

Question 19 of 23

1.0 Points

A set of final exam scores in an organic chemistry course was found to be normally distributed, with a mean of 73 and a standard deviation of 8.

Only 5% of the students taking the test scored higher than what value? Place your answer, rounded to a whole number, in the blank. For example, 78 would be a legitimate entry.

Part 13 of 16 –

Question 20 of 23

1.0 Points

The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan. A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228.

Construct a 95% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation.

Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 123.4 would be a legitimate entry.

Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry.

Part 14 of 16 –

Question 21 of 23

1.0 Points

In February 2002 the Argentine peso lost 70% of its value compared to the United States dollar. This devaluation drastically raised the price of imported products. According to a survey conducted by AC Nielsen in April 2002, 68% of the consumers in Argentina were buying fewer products than before the devaluation, 24% were buying the same number of products, and 8% were buying more products. Furthermore, in a trend toward purchasing less-expensive brands, 88% indicated that they had changed the brands they purchased. Suppose the following complete set of results were reported. Use the following data to answer this question.

Brands Purchased

Number of Products Purchased

Same

Changed

Total

Fewer

10

262

272

Same

14

82

96

More

24

8

32

Total

48

352

400

What is the probability that a consumer selected at random purchased the same number or more products than before? Place your answer, rounded to 4 decimal places, in the blank.

Part 15 of 16 –

Question 22 of 23

1.0 Points

Suppose a firm that produces light bulbs wants to know whether it can say that its light bulbs typically last more than 1500 hours. Hoping to find support for their claim, the firm collects a random sample of n = 25 light bulbs and records the lifetime (in hours) of each bulb. The information related to the hypothesis test is presented below.

Test of H0: f$muleq f$ 1500 versus H1:f$mu f$ > 1500

Sample mean 1509.5

Std error of mean 4.854

What is the test value that you would use to conduct this test? Place your answer, rounded to 3 decimal places in the blank. For example, 1.234 would be a legitimate entry.

Part 16 of 16 –

Question 23 of 23

1.0 Points

If a coin is tossed seven times, how many different outcomes are possible? Place your answer in the blank. Do not use any decimal places or commas. For example, 345 would be a legitimate entry.